Answer:
C. 15
Step-by-step explanation:
Assuming that these segments formed from each parallel line are proportional, x/5 = x-6/3.
Now cross multiply by multiplying each denominator by the opposite numerator, this is so the denominators or bottom numbers of each fraction will cancel.
x/5 = x–6/3 → (3)(x/5) = (3)(x–6/3) → 3x/5 = x–6 →
(5)(3x/5) = (5)(x–6) → 3x = 5(x–6) → 3x = 5x – 30.
The last step is to do the basic algebra to find x:
3x = 5x – 30
–5x –5x
[5x will cancel when you subtract both sides by 5x]
-2x = -30
(-1) (-1)
[2 negatives make a positive when -1 is multiplied by an expression with a negative coefficient]
2x = 30
÷2 ÷2
[divide both sides by 2 to simplify 2x to x]
x = 15
_____
You can also check that both sides are proportional because
5 → x
x = 15
5 → 15
3 → x – 6
x = 15
3 → 9
5 × 3 = 15
3 × 3 = 9
