Question

Malloy solved the equation −5x − 16 = 8; his work is shown below. Identify the error and where it was made. −5x − 16 = 8 Step 1: −5x − 16 + 16 = 8 + 16 Step 2: −5x = 24 Step 3: negative five times x over five = twenty-four over five Step 4: x = twenty-four over five

Answer 1

Error in step 3

`(-24)/(5)`

Explanation:

−5x − 16 = 8

Step 1: −5x − 16 + 16 = 8 + 16

Step 2: −5x = 24

Step 3: -5x/5 = -24/5

Step 4: x = 24/5

Step 1 and step 2 are correct

In step 3 we need to eliminate -5

so we divide both sides by -5

Malloy divided both sides by 5 instead of -5

so step 3 becomes

`(-5x)/(5) =(24)/(-5)`

step 4 :
`(-24)/(5)`

Answer 2

-5x - 16 = 8
-5x - 16 + 16 = 8 + 16 (step 1...correct)
-5x = 24 ( step 2...correct)
-5x/5 = 24/-5 (step 3...incorrect..he didn't divide both sides by -5)
x = -24/5