How do you find the intercepts for y= x^2+4x-5y=x2+4x5?

1 Answer
Apr 4, 2018

y-intercept
y=-5y=5

x-intercepts
x_1 =-5x1=5
x_2 =1x2=1

Explanation:

an x-intercept is a point where y=0y=0, and
a y-intercept is a point where x=0x=0

x-intercepts: 0=x^2 + 4x -50=x2+4x5

x^2 + 4x -5+ (4/2)^2=0+ (4/2)^2x2+4x5+(42)2=0+(42)2 complete the square
(x + 2)^2 -5=4(x+2)25=4
(x + 2)^2 =9(x+2)2=9
x + 2=± 3x+2=±3
x =-2± 3x=2±3

x_1 =-5x1=5
x_2 =1x2=1

y-intercept: y=(0)^2 + 4(0) -5=-5y=(0)2+4(0)5=5

Check the graph

graph{x^2 + 4x - 5 [-9.96, 10.04, -8.72, 1.28]}