Question

Given the equation 4x + 7 = 3(2x − 5), solve for the variable. Explain each step and justify your process.

B.Sam solved a similar equation below. Is Sam's solution correct? Explain why or why not.
5x − 1 = 2(x + 4)
5x − 1 = 2x + 8
7x − 1 = 8
7x = 7
x = 1

Answer 1

Part 1:
`4x + 7 = 3(2x - 5)`


`4x+7=6x-15`


`7=6x-15-4x`


`7=2x-15`


`7+15=2x`


`22=2x`


`22=2x / 2`


`x=11`

Part 2: Sam is not correct because he messed up the second step. He added 2x on both sides to get 7x, instead he should have subtracted.