Ask Dr. Math Middle School Archive

Dr. Math Home || Elementary || Middle School || High School || College || Dr. Math FAQ

 TOPICS This page:   algebra    Search   Dr. Math See also the Dr. Math FAQ:   order of operations Internet Library:   basic algebra T2T FAQ:   algebra help MIDDLE SCHOOL About Math Algebra    equations    factoring expressions    graphing equations Arithmetic    division    exponents    factorials    factoring numbers    fractions/percents    logarithms Definitions Geometry    2-dimensional      conic sections/        circles      triangles/polygons    3D and higher      polyhedra History/Biography Logic Measurement    calendars/      dates/time    temperature    terms/units Number Sense    factoring numbers    negative numbers    pi    prime numbers    square roots Probability Puzzles Ratio/Proportion Statistics Word Problems Browse Middle School Algebra Stars indicate particularly interesting answers or good places to begin browsing. Selected answers to common questions:     Direct and indirect variation.     Inequalities and negative numbers.     Positive/negative integer rules.     Solving simple linear equations. Sets and Subsets [1/23/1995] My teacher said that integers are a subset of reals, and whole numbers are a subset of integers, and counting numbers are a subset of whole numbers, and so on and so forth. What does that mean? Several Ways to Solve a Rate-Time-Distance Problem [02/14/2006] A bus leaves point A travelling at a speed of 10 mph. 22 minutes later a car leaves point A travelling in the same direction as the bus at 40 mph. At what distance will the car catch the bus, and how much time will have elapsed since the car left point A? Shadow Game [01/28/2001] Tom is 6 feet tall and Carol is 5 feet tall. If Carol stands at the "shadow top" of Tom's head, their two combined shadows total 15 feet. How long is each shadow? Sharing the Cost of the Weekend Trip [07/24/2003] A group of people planned to rent a large beach house for a weekend trip. They were to share the \$800 cost equally. However, two people were unable to go and this increased the cost for each person by \$20. How many persons were in the original group? Shortcut for Comparing Fractions [01/14/2003] My teacher showed us how to cross multiply to compare fractions. Sierpinski Gasket [8/29/1995] What is the area of a Sierpinski gasket? Sign Switching [01/28/2002] Can you explain sign switching in multiplying and dividing inequalities? Simple Algebraic Equations [5/26/1996] How do you logically solve simple algebraic equations? Simple Equation: 3y + 2 over 4 equals 7 [10/17/2001] I think you have to subtract 2 on both sides, but I'm lost. Simplification Problems [8/20/1996] Simplify 2x(4-2x+y) - 5x(y^2+x-y) Simplify an Expression [6/15/1996] Simplify (9a+2b)-(4a-3b) Simplifying a Fraction -- and Oversimplifying It [03/03/2012] A student simplifies a fraction by selectively canceling terms. Doctor Peterson compares the algebraic expression before and after such unbalanced steps, revealing how this method does not maintain equality. Simplifying an Algebraic Fraction [05/09/2000] How can I simplify 1 + 1/(x + 1/x)? I can't figure out the common denominator. Simplifying an Expression [04/29/1999] Can you help me figure out (x+3)+(4x-7)+(x-20) ? Simplifying an Expression [05/04/1999] How do you simplify 9x - 3x + 7 - 4x + y - 3 ? Simplifying Expressions [8/31/1996] How do I simplify (y + 3) - 2(y + 7) ? Simplifying Expressions [01/27/1997] How do you simplify 3x - 2y - x -3y? Simplifying Expressions [11/24/1997] Solve: 2x - ( 3 - x ) = x - 7 . Simplifying Mixed Algebraic Expressions [05/08/1998] Simplifying fractions such as 2x - (x+y)/y and 4 - 3/(y-1) - 1/(y+1). Simplifying Polynomials [4/26/1996] How do you simplify polynomials? Simplifying Using the Distributive Property [09/07/99] How do you simplify an expression like 12(c+3d+4e) + 2(2c+d+6e)? Simplifying with Cube Roots [01/22/1997] Simplify: cube root(3) / [cube root(6) + cube root(3)] Simultaneous Equations [8/25/1996] Ten percent of the reds were added to twenty percent of the blues, and the total was 24... Simultaneous Equations [08/10/1997] A, B, and C can finish a job in 6 days... In how many days can each man working alone do the job? Simultaneous Equations [07/01/2002] A man has a total of 20 dimes and quarters. If the dimes were quarters and the quarters were dimes he would have 90 cents more than he has now. How many of each coin does he have? Six Chickens, Five Minutes [01/09/2003] If 1 and 1/2 chickens lay 1 and 1/2 eggs in 1 and 1/2 minutes, how many eggs will 6 chickens lay in 5 minutes? Slope and (x, y) Intercept [02/19/1999] Does slope depend on (x, y) intercept or does (x, y) intercept depend on slope? Slope-Intercept Formula [06/05/2001] Why does y = mx + b have to be that way? Solutions to Equations [01/16/1997] How do you make a table of values of x and y that make the equation 3/4y = -x true? Solution Using Verbal Argument and Model [02/06/2002] Mr. Li has fewer than 200 sweets. He wants to give each pupil in his class an equal number of sweets. If he gives each pupil 2 sweets, he will have 70 sweets left over; if 4, he will need 10 more sweets. How many pupils are there in the class? How many sweets does Mr. Li have? Solve 2x + 3 = 10 [09/17/2001] I don't understand what to do to simplify the problem. Solve for g... [04/08/1997] I understand -3x+5x+4 = -6 to solve for x, but I don't understand g+.04g+60 = 8796. Solve Using Elimination [01/24/2001] Solve by using elimination, and check solutions: x+6y=20, x+2y=12. Solving a Fraction Problem Using Common Sense [03/21/2004] When the gun sounded, only two-fifths of the racers began to run. If 460 racers began to run, how many racers were there in all? Can you show me how to figure out what a fraction is without knowing the total number? Solving a Linear Equation in One Variable [02/27/1998] Solve for q: -13 - q - 9 = 5q - 9 - q. Solving a Math Poem [05/24/2000] Take five times which plus half of what, and make the square of what you've got... Solving a Mixture Problem Intuitively and with Algebra [07/06/2007] There are 7 litres of turpentine in a mixture of 21 litres of water and turpentine. How many litres of turpentine must be added to make a mixture of 75% turpentine? Solving an Algebraic Equation [12/21/1995] If x = 2y = 3z = 1,then what is x(y-z)squared + y(z-x)squared + z(x- y)squared? Solving an Equation with two Variables [11/20/1995] The problem is n + n + 5 = 25. How do I do this? It has two variables. Solving a Rational Inequality [11/15/2004] How do you solve a rational inequality like (x-1)/(x+3) < 3? Page: []

Search the Dr. Math Library:

 Search: entire archive just Middle School Algebra Find items containing (put spaces between keywords):   Click only once for faster results: [ Choose "whole words" when searching for a word like age.] all keywords, in any order at least one, that exact phrase parts of words whole words

[Privacy Policy] [Terms of Use]

© 1994- The Math Forum at NCTM. All rights reserved.
http://mathforum.org/