Question

Solve systems of equations

-x^2-4x+y=0
-x^2+9x+y+13=0

Answer 1

I solve it by substitution

y=x^2+4x

-x^2+9x+(x^2+4x)+13=0

13x+13=0

13x=-13

x= -13/13

x= -1

y=x^2+4x=1-4

y= -3

Explanation: