The sum of the first number & the square of a second number is 18. The difference between the square of the second number and twice the first number is 12.

Question

Write a system of equations to represent this situation.
y=-x^2+18
y=.5x^-6

Solve the system to determine the numbers:
2 & 4

The roots are 4 & -4 but 2 & 4 are the correct answer as to what the 2 numbers were, correct?

Thank you! :)

Answer 1

y+x^2 = 18
x^2-2y = 12

eliminate x^2 and you have
18-y = 2y+12
3y = 6
y = 2
so, x^2 = 16, making (-4,2) and (4,2) possibilities.
If they meant positive numbers, then only (4,2) is the answer.