Math

These questions and your answers to them will tell you what kinds of math concepts and problems you need to concentrate on studying.  Try to complete this section in 7 minutes.

Answer the following questions:

1. If 2x + 3y = 4 and y = 2, find the value of x.

A) +2
B) +1
C)   0
D) -1
E) -2

(A) Perhaps you were just careless. Did you think that if 2x + 6 = 4 that 2x = 2, and choose 2 as the answer? Choice D is correct. Here's the correct way:

Use Strategy 7, p. 88; BASIC SKILL - Mini-Math refresher- Equations, p. 158; Math Refresher (407), p. 244: Substitute numbers for variables. Substitute y = 2 into the equation, 2x + 3y = 4. You get 2x + 6 = 4; 2x = -2, so x = -1.

(B) Perhaps you were just careless. Did you subract 6 from 4 and get 2? Choice D is correct Here is correct way:

Use Strategy 7, p. 88; BASIC SKILL - Mini-Math refresher- Equations, p. 158; Math Refresher (407), p. 244:
Substitute numbers for variables. Substitute y = 2 into the equation, 2x + 3y = 4. You get 2x + 6 = 4; 2x = -2, so x = -1.

(C) Choice D is correct. Here is the correct way:

Use Strategy 7, p. 88; BASIC SKILL - Mini-Math refresher- Equations, p. 158; Math Refresher (407), p. 244:
Substitute numbers for variables. Substitute y = 2 into the equation, 2x + 3y = 4. You get 2x + 6 = 4; 2x = -2, so x = -1.

(D) Right! Use Strategy 7, p. 88; BASIC SKILL - Mini-Math refresher- Equations, p. 158; Math Refresher (407), p. 244: Substitute numbers for variables. Substitute y = 2 into the equation, 2x + 3y = 4. You get 2x + 6 = 4; 2x = -2, so x = -1.

(E) Perhaps you were just careless. Did you think that if 2x + 6 = 4 and 2x = -2, then x = -2? Choice D is correct. Here is the correct way:

Use Strategy 7, p. 88; BASIC SKILL - Mini-Math refresher- Equations, p. 158; Math Refresher (407), p. 244:
Substitute numbers for variables. Substitute y = 2 into the equation, 2x + 3y = 4. You get 2x + 6 = 4; 2x = -2, so x = -1.