Question

myra is evaluating the expression (-31.7 + 4.5x), when (x = 2.1).
(-31.7 + 4.5(2.1))
(-27.2(2.1))
(-57.12)
what was myra’s error?
○ myra should have multiplied (-31.7) and (2.1) first.
○ myra should have multiplied (4.5) and (2.1) first.
○ myra should have subtracted (-27.2) and (2.1) first.
○ myra should have added (-31.7) and (2.1) first.

Explanation:

Step1: Recall order of operations

Follow PEMDAS/BODMAS: Multiply before add.

Step2: Identify Myra's mistake

Myra added $-31.7 + 4.5$ first, instead of multiplying $4.5(2.1)$ first.

Step3: Match to correct option

The error is failing to do multiplication first.

Answer:

B. Myra should have multiplied 4.5 and 2.1 first.