Question

If (y+2) (y+4) +1=0, then which of the following is correctly A. Y=3, 3
B. Y=-2, -4
C. Y=2, 4
D. Y=-3, -3

Answer 1

D. y=-3,-3

Explanation:

Given:

(y+2) (y+4) +1=0

To find:

The roots

Step1:

==> Multiply the value to change it as a quadratic equation

==> (y+2) (y+4) +1=0

==> y(y+4)+2(y+4)+1=0

==> y²+4y+2y+8+1 =0

==> y²+6y+9 =0

Step2:

==> Find the zeros from the equation

==> sum of the zero = b

==> product of the zero = a×c

==> a= coefficient of y²

==> b= coefficient of y

==> c= constan

==> a = 1

==> b=6

==> c=9

==> Sum of the zero = 6

==> Product of the zero = 1×9=9

The two number be x and y

==> x+y = 6

==> xy = 9

==> 3+3=6

==> 3×3=9

Step 3:

==>  y²+3y+3y+9=0

==>  y(y+3)+3(y+3)=0

==> (y+3)(y+3)=0

==> y+3 =0 , y+3 =0

==> y =-3, y=-3

Option d is correct