Answer:
X = 9,X= -5, a = 2, b = -13
Explanation:
For (1),
Using Cross-factorization,
it can be reduced to (X - 9)(X + 5) = 0
Equate each factor to 0:
we have X = 9 and X = -5
For (2),
It is the case of completing the Square,
add 4 so we get the completed square ( we want the form X^2 + 2a + a^2)
(X^2 + 4X + 4) - 9
can be simplified to (X+2)^2 -9
However since we added 4 it means we have to subtract 4
So it becomes (X+2)^2 -9 -4
= (X+2)^2 -13