A number increased by 7 is equal to 13 less than the square of the number.

Question

I need the equation. Please and thank you.

Answer 1

x+7=x^2-13

Answer 2

If N is the number: N+7=N^2-13. The equation is a quadratic: N^2-N-20=0, which factorises: (N-5)(N+4)=0. If the number is positive, it's 5; if negative it's -4. Add 7 to each of these alternative solutions: 12 and 3. Square each number: 25 and 16, then subtract 13: 12 and 3.