Question

From the set {-252, -64, 64}, use substitution to determine which value of x makes the equation true.

4x = 256
A.
-64
B.
64
C.
none of these
D.
-252

Answer 1

9514 1404 393

Answer:

x = 64

Explanation:

I find it easier to solve the equation, which requires 1 operation. Substituting 3 numbers requires 3 operations, so is 3 times the work. (I'm basically lazy.)

4x = 256 . . . . given

x = 256/4 = 64 . . . . the last of the listed values

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Alternatively, you can let a graphing calculator or spreadsheet try the list of values for you. That result is attached.

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Since you know the rules of signed multiplication, you know that x must be positive. Only one answer choice is positive, so you really only need to try one number.

4(64) = 256 . . . . true, so x = 64