Question

Find the exact solution(s) of each system of equations?
x^2+y^2=25 and 9y=4x^2

a.(4,3),(-4,3)
b.(3,4),(3,-4)
c.(4,3),(4,-3)
d.(3,4),(-3,4)

I had d but im not sure if that is right.

Answer 1

Let's see if d satisfies the equations.
x=3 and y = 4
equation 1.
3^2 + 4^2 = 25
9 + 15 = 25 OK on this one.

x = -3 and y = 4
equation 2.
9*(-3) = 4*(4^2)
-27 = 4*16
-27=64 so d isn't right. The first set satisfied the first equation but the second set did not satify the second equation.