View Full Version : Pre-Calculus - first the basics
UnSolon
Jan 26, 2006, 08:20 AM
Find the points of intersection of the graphs of the equations:
x^2 + y^2 = 5
x - y = 1
Pretty basics, but lets see who's up on calc.
fredg
Jan 26, 2006, 08:49 AM
Hi,
x intercepts are -1 and 2
y intercepts are -2 and 1
reinsuranc
Jan 26, 2006, 09:24 PM
x^2 + y^2 = 5
x = y + 1
(y+1)^2 + y^2 = 5
y^2 +2y +1 +y^2 - 5 =0
2y^2 + 2y -4 = 0
y^2 +y -2 = 0
(y + 2)(y - 1) = 0
y roots are -2 and +1.
corresponding x values are -1 and 2.
Solutions are (-1,-2), (2,1)
UnSolon
Jan 26, 2006, 11:02 PM
Very good... correct on all counts