You’re given g(x) = x^2 - 5
When asked to find g(9), you’re being told that x=9, since the x in the g(x) was replaced by 9.
So that’s telling you to put 9 in for all x’s:
g(9) = (9)^2 - 5
You then just need to clear up the right hand side.
9^2 - 5 = 81 - 5
= 76
So, g(9) = 76
You cannot simplify the fraction 4/21, because you would have to divide 21 by 4, which would end in a decimal answer, therefore you cannot simplify it.
Lwh=v
2*w*(w+2)=48
2w^2+4w=48
w^2+2w-24=0
(w+6)(w-4)=0
w= - 6 or w= 4
Since w cannot be negative, then w=4.
