Question

Margo solves several equations and then states that all of them have a solution of x = 7. However, Kenneth disagrees. Determine which of the following equations have a solution of x = 7 and then justify your response.

A. 6x + 11 = 55
B. -3x -18 = 39
C. 2x - 14 = - 28
D. 7x + 9 = 58
SHOW YOUR WORK!!!​

Answer 1

a.
`6x+11=55`

Subtract 11 from both sides:

`6x+11-11=55-11`

`6x=44`

Divide both sides by 6:

`(6x)/(6) =(44)/(6)`

`x=7.333333`

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b.
`-3x-18=39`

Add 18 to both sides:

`-3x-18+18=39+18`

`-3x=57`

Divide both sides by -3:

`(-3x)/(-3) =(57)/(-3)`

`x=-19`

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c.
`2x-14=-28`

Add 14 to both sides:

`2x-14+14=-28+14`

`2x=-14`

Divide both sides by 2:

`(2x)/(2) =(-14)/(2)`

`x=-7`

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d.
`7x+9=58`

Subtract 9 from both sides:

`7x+9-9=58-9`

`7x=49`

Divide both sides by 7:

`(7x)/(7) =(49)/(7)`

`x=7`

___________________________

Only option d had a solution of x = 7.