Add 7 to both sides
3x + 12 = 7x
Subtract 3x
12 = 4x
Divide by 4
x = 3
Answer:
Real, rational
Step-by-step explanation:
It's the last option again. You have 1 linear factor (3<em>x</em>) and 2 copies of a quadratic factor (<em>x</em>² + 10), and the partial fractions with the quadratic factor need to have a linear polynomial in the numerator.
Answer:

Step-by-step explanation:
The question is not correct (particularly the expression for the area)
A=2lh+2wh
Now we are expected to solve for l, that is we are going to make l subject of the formula, we have
let us take the second term on the RHS to the LHS

we can now divide both sides by 2h we have

hence the expression for the length is 
(x - 3) + (x - 6) + x = 63
x - 3 + x - 6 + x = 63
Combine like terms
3x - 9 = 63
Isolate the constant
3x - 9 + 9 = 63 + 9
3x = 72
Isolate the viable
3x / 3 = 72 / 3
x = 24