The formula states that:
Faces + Vertices - Edges = 2
So 21 + V - 49 = 2 => V = 2+49-21 = 30
Answer A!
We know: length of a rectangle is 7m less than three times the width.
So let's set the length to l, width to w.
And we can get that l = 3w-7.
We also know that the area of the rectangle is 66 m^2.
Thus, l*w= 66.
So we have:
function 1: l=3w-7
function 2: l*w=66
plug function 1 to 2.
(3w-7)*w=66
3w^2-7w-66=0
w=6 and -11/3.
And the width of a rectangle can not be negative.
So: w=6.
Plug w=6 back to function 1 or 2, either way is correct and can give you the length. In this case, I will plug it back to function 1.
l=3*6-7=11.
So: the width of the rectangle is 6, and the length of the rectangle is 11.
3*x/4=24
3*x= 24*4
3x=96
3x/3=96/3
x=32
