SOLUTION: Find the x intercepts f(x)=2x^2 +8x-42 (2x+6)(x-7) x+3 X-7 intercepts are - 3 and 7 is this correct?????

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Question 194574: Find the x intercepts
f(x)=2x^2 +8x-42
(2x+6)(x-7)
x+3 X-7
intercepts are - 3 and 7 is this correct?????

Found 2 solutions by stanbon, jojo14344:
Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
Find the x intercepts
f(x)=2x^2 +8x-42
---
Let y = 0
2x^2 + 8x - 42 = 0
2(x^2 + 4x - 21) = 0
Factor:
2(x+7)(x-3) = 0
x = -7 or x = 3
========================
Cheers,
Stan H.

Answer by jojo14344(1513)   (Show Source): You can put this solution on YOUR website!


Given: f(x)=2x^2 +8x-42
Simplified by dividing the whole eqn by 2:

, perfect square
So,
Then, ; , X-Intercepts.

To follow up on this, let us find the vertex:

Complete the square:



Vertex: (-2,-25)

Since a>0, (a=1), the parabola opens upwards.


Thank you,
Jojo

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