Let "a number" be x. Three times this is 3x. This is equal to x-7 (3x=x-7). Add a -x to isolate the number. This leaves you with 2x=-7. Divide by 2, and you're left with x=-3.5.
Simply jot down the inequalities as they are presented in the word problem and match up to the answer selection. That leaves Answer 3.
STEP ONE. Separate the two variables and get rid of the 0 (2x=-2y).
STEP TWO. Divide by 2 (x=-y).
STEP THREE. Plug in -y for x and solve. This leaves Answer 1.
STEP ONE. Pull out your four to simplify the equation.
STEP TWO. Solve for the two resulting equations. Answer 2 is the correct choice.
STEP ONE. Add the two equations (7a+7b=77).
STEP TWO. Divide by 7 (a+b=11). Answer 4 is the correct choice.
Simple enough answer choices. Simply plug in the numbers into the simpler equation. This will help produce a potential answer for y as well. You can then check your answers in both equations to make sure they "fit."
A careful reading of the word problem will leave you with the following: 3x=x+6, 5x+20-x
3x=x+6
ADD -x 2x=6
DIVIDE by 2 x=3
5x+20-x=32
SIMPLIFY x 4x+20
SUBSTITUTE 3 for x, adds up to 32, Answer 3.
Start with 4y=y+4.
ADD -y to both sides 3y=4
DIVIDE by 3 y=4/3
SUBSTITUTE 4/3 for y and MULTIPLY * 3.
SIMPLIFY FRACTION THROUGH DIVISION. Answer 4.
The cost is $5 per month (5m). The +12 accounts for the one-time purchase price. To solve for the two-year question, you would simply need to plug 24 into m (for 24 months in two years). Since the question is not asking for the actual number, but the equation, Answer 1 is the correct choice.
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SAT Practice Test #4
