I think the answer is (-6,30) unless I messed up somewhere
6x^2 - 8 = 4x^2 + 7x
6x^2 - 4x^2 - 7x - 8 = 0
2x^2 - 7x - 8 = 0
discriminant = b^2 - 4ac; where a = 2, b = -7 and c = -8
d = (-7)^2 - 4(2)(-8)
d = 49 + 64
d = 113
the discriminant is greater than zero, so there are two real roots
Plug in 3 for f(x)
f(3)=(3)²+7
f(3)=9+7
f(3)=16
Hoped this helped!
Easy I guess ..
I ll try to help ..
Here we go ..
The cards you have is N
The cards he has is n
<span>you have 3 times the number of cards he has
This means N=3n
</span><span> you only have 80 more football cards then he does
This means N=n+80
But we already know that N=3n
So 3n=n+80
which is 2n=80
n=40
So your friend has only 40 cards and you have 3*40= 120 cards
Best luck
Wise</span>
