Answer:
-3x+8/4(x-9)(x+12)
Step-by-step explanation:
x
2
+3x−108
7
−
4x−36
3
Factor x
2
+3x−108. Factor 4x−36.
(x−9)(x+12)
7
−
4(x−9)
3
To add or subtract expressions, expand them to make their denominators the same. Least common multiple of (x−9)(x+12) and 4(x−9) is 4(x−9)(x+12). Multiply
(x−9)(x+12)
7
times
4
4
. Multiply
4(x−9)
3
times
x+12
x+12
.
4(x−9)(x+12)
7×4
−
4(x−9)(x+12)
3(x+12)
Since
4(x−9)(x+12)
7×4
and
4(x−9)(x+12)
3(x+12)
have the same denominator, subtract them by subtracting their numerators.
4(x−9)(x+12)
7×4−3(x+12)
Do the multiplications in 7×4−3(x+12).
4(x−9)(x+12)
28−3x−36
Combine like terms in 28−3x−36.
4(x−9)(x+12)
−8−3x
Expand 4(x−9)(x+12).
4x
2
+12x−432
−8−3x
