How do you solve x^2+y^2=25, 4x+3y=0x2+y2=25,4x+3y=0?

1 Answer
Feb 18, 2017

(-3, 4) and (3, -4)(3,4)and(3,4)

Explanation:

x^2+y^2=25x2+y2=25
4x+3y=04x+3y=0 => solve for y in terms of x:
3y=-4x3y=4x
y=(-4x)/3y=4x3 => substitute in the first equation:
x^2+[(-4x)/3]^2=25x2+[4x3]2=25
x^2 +(16x^2)/9=25x2+16x29=25 => multiply all terms by 9:
9x^2+16x^2=25*99x2+16x2=259
25x^2=25*925x2=259
x^2=9x2=9 => solve for x:
x=+-3x=±3
x=-3, y=4x=3,y=4
x=3, y=-4x=3,y=4
What we have is a straight line(2nd equation) that intercepts a circle(1st equation) in the above points(the solutions)