Question

Please help!

What are the x-coordinates of the solutions to this system of equations?
x2 + y2 = 16
y = x + 4

Answer 1

put y=x+4 in eq 1

x2+(x+4)^2=16
=>x2+x2+16+4x=16
=>2x2+4x=0
=>2x(x+4)=0
=>x=0,-4

Answer 2

Thank you so much! I have a question (x+4)(x+4)= x^2+8x+16 right? So how I get how you got x^2+x^2=2x^2 but what about the 8x

Answer 3

(x+4)(x+4)=(x+4)^2

so use it
(a+b)^2=a2+b2+2ab

and sorey...you are right.its 8x not 4x..


so factrs regarding x=0,-8

Answer 4

my mistake..

Answer 5

Ohhh..thank you so much!