Answer:
The answer is 2(5x - 4)(x + 1)
Explanation:
In this case, use the shortcut, since (a - b + c) = 0. One factor is (x + 1) and the other is (x + c/a = - 8/10).
y = (x + 1)(10x - 8) = 2(x + 1)(5x - 4)
You may also use the new AC Method.
Converted
y
'
=
x
2
+
2
x
−
80
=
(
x
−
p
'
)
(
x
−
q
'
)
.
Factor pairs of (-80) -> ...(-4, 20)(-8, 10). This sum is 2 = b. Then p' = -8 and q' = 10.
Then,
p
=
p
'
a
=
−
−
8
10
and
q
=
q
'
a
=
10
10
=
1
.
y = 10(x - 8/10)(x + 1) = (10x - 8)(x + 1)= 2(5x - 4)(x + 1)