If you graph the two equations then you will find that they intersect at (-2,-2).
You then have to check your answer.
x=4y+6
(-2)=4(-2)+6
-2=-8+6
-2=-2
x-3y=4
(-2)-3(-2)=4
-2+6=4
4=4
The answer is 78
If you multiply 17x6 you get 102
102 equals the whole rectangle after that you need to get rid of the part that’s not there
so you multiply 8x3 which equals 24
you then subtract 24 from 102 and get 78
The final answer is (-25)
S = 4pi r^2
S/4pi = r^2
taking square root on both sides,
r = sqrt (S/4pi)