To solve the system, we need to set the two equations equal to each other. However, we need to manipulate the equations so they equal the same thing.
y=x^2-9x+10
x+y+5=0
y= -5-x
Now that we have two equations that both equal y, we can set them equal to each other and solve for x.
-5-x=x^2-9x+10
0=x^2-8x+15
0=(x-5)(x-3)
0=x-5 0=x-3
x=5 x=3