Question

if one root of ax²+2x+7is (-2),then the value of a is?

Answer 1

Heya!!!

Let the polynomial ax^2 + 2x + 7 be f (x) .
Then,

Since, (-2) is root or zero of f (x)

F (-2) = 0

=) a (-2)^2 + 2 (-2) + 7 = 0

=) 4a - 4 + 7 = 0

=) 4a + 3 = 0

=) 4a = -3

=) a = -3/4

Hence, the value of a is -3/4.

Hope it helps u.
-)

Answer 2

Let x= -2
p(x) = ax²+2x+7
putting the value of x.
p(-2) = a (-2)²+2(-2)+7= 0
= 4a-4+7=0
= 4a=-7+4
=4a= -3
= a = -3 /4