230k views
5 votes
Why is the answer C? Plz explain

Why is the answer C? Plz explain-example-1
User Foxesque
by
8.3k points

1 Answer

1 vote
Set the equations each to each other and solve for x
f(x) = g(x)
x^2 - 3x = 2x+14
x^2-3x-2x-14 = 0
x^2-5x-14 = 0 .... see note below
(x-7)(x+2) = 0
x-7 = 0 or x+2 = 0
x = 7 or x = -2
The two solutions are x = 7 or x = -2

note: we technically could stop at this line and divert to another path. Instead of finding the actual solutions, we can use the discriminant formula
d = b^2 - 4ac
to find the value of d. It turns out that
d = (-5)^2 - 4(1)(-14)
d = 81
which is a positive number. So that shows we have two solutions.
User Krishnamoorthy
by
8.3k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.