This is another “plug-in” question. Remember, 5yz means 5 • y • z. First we will replace x, y, and z with the values given.
Then we will carry out the indicated operations using the PEMDAS order of operations—Parentheses, Exponents,
Multiplication and Division, Addition and Subtraction.
H
If you look carefully at the expression 2 x + 2y − 2, you should see some similarity to x + y = 7. If we ignore the −2 for a
moment, 2 x + 2y is really just twice x + y. If it helps to make it clearer, we can factor out the 2, making 2 x + 2y into 2(x + y).
Since x + y = 7, 2(x + y) must equal 2(7), or 14. If we replace 2 x + y with 14, the expression 2 x + 2y − 2 becomes 14 − 2,
which equals 12, or choice (H).
6.
C
Plug in 18 for b in the equation:
3 a − 6 = 18
Isolate a on one side of the equation:
3 a =18 + 6
3 a = 24
Divide both sides by 3 to find the value of a:
a = 8
7.
J
Substitute 10 for x in the equation:
Cross multiply:
8.
