What Is The Solution Of This Answer??

What is the solution of this answer??

  First, lets factor it out. Lets find the factors of 9, we have 1, 9. Then, lets find the factors of d^2, it gives us d and another d.

Make 2 parentheses.
( )( )
Fill it with
2 "d"s
(d )(d )

Since the quadratic equations operations are all addition put the symbol "+" in the parentheses, right after d.
(d + )(d + )

Next, put 1 and 9 after the "+" symbol
(d + 1)(d + 9)

Lets check if its right!
Apply the FOIL METHOD
F = d • d
O = 9 • d
I = 1 • d
L = 9

Resulting to,
d^2 + 9d + d + 9
Then simplify
d^2 + 10d + 9

So its correct!

Finally, separate the two factors
(d + 1)
---
(d + 9)

Do this,

(d + 1) = 0
(d + 9) = 0

Equate the two "d"s

On the first equation, subtract 1 to both sides making d = -1
On the second equation, subtract 9 to both sides making d = -9

There you have it! The solutions are -1 and -9