Question 593875
Find the points of intersection of the graphs of the equations. 
x^2 + y^2=25
-2x + y=10
**
-2x + y=10
y=2x+10
..
x^2 + y^2=25
x^2 + (2x+10)^2=25
x^2+4x^2+40x+100=25
5x^2+40x+75=0
x^2+8x+15=0
(x+3)(x+5)=0
x+3=0
x=-3
y=2x+10=-6+10=4
and 
x+5=0
x=-5
y=2x+10=-10+10=0
..
Points of intersection: (-3,4) and (-5,0)