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

Error in step 3

Step-by-step 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

step 4 :  

simplifying

5(x + -6) = 2(x + 3)

reorder the terms:

5(-6 + x) = 2(x + 3)

(-6 * 5 + x * 5) = 2(x + 3)

(-30 + 5x) = 2(x + 3)

reorder the terms:

-30 + 5x = 2(3 + x)

-30 + 5x = (3 * 2 + x * 2)

-30 + 5x = (6 + 2x)

solving

-30 + 5x = 6 + 2x

solving for variable 'x'.

move all terms containing x to the left, all other terms to the right.

add '-2x' to each side of the equation.

-30 + 5x + -2x = 6 + 2x + -2x

combine like terms: 5x + -2x = 3x

-30 + 3x = 6 + 2x + -2x

combine like terms: 2x + -2x = 0

-30 + 3x = 6 + 0

-30 + 3x = 6

add '30' to each side of the equation.

-30 + 30 + 3x = 6 + 30

combine like terms: -30 + 30 = 0

0 + 3x = 6 + 30

3x = 6 + 30

combine like terms: 6 + 30 = 36

3x = 36

divide each side by '3'.

x = 12

simplifying

x = 12

this should .