Question

3. Find the value for x that makes the following equation true.

3x - 7 = x + 3
A)x = -5
B) x = 2
C) x = 5
D) x = -2


Can someone please help me out ??

Answer 1

C) x = 5

Explanation:

A) 3(-5) - 7 = (-5) + 3

-15 - 7 = (-5) + 3

-23 = (-5) + 3

-23 = -2 (they do not equal the same so no)

B) 3(2) - 7 = (2) + 3

6 - 7 = (2) + 3

-1 = (2) + 3

-1 = 5 (they do not equal the same so no)

C) 3(5) - 7 = (5) + 3

15 - 7 = (5) + 3

8 = (5) + 3

8 = 8 (they equal the same so yes)

D) 3(-2) - 7 = (-2) + 3

-6 - 7 = (-2) + 3

-13 = (-2) + 3

-13 = 1 (they do not equal the same so no)

Answer 2

C

Explanation:

So we have the equation:

`3x-7=x+3`

Subtract x from both sides. The right cancels:

`(3x-7)-x=(x+3)-x\\2x-7=3`

Add 7 to both sides. The left cancels;

`(2x-7)+7=(3)+7\\2x=10`

Divide both sides by 2:

`(2x)/2=(10)/2\\x=5`

So, our answer is C