Question

How do you find the x and y intercepts for `y=x^2+6x-5`?

Answer 1

x-intercept --> `-3 +- sqrt14`

Explanation:

To find y-intercept, make x = 0 --> y = -5
To find x-intercepts, make y = 0 and solve the quadratic equation:
`y = x^2 + 6x - 5 = 0.`
`D = d^2 = b^2 - 4ac = 36 + 20 = 56 = 4*14` --> `d = +- 2sqrt14`
`x = - 6/2 +- (2sqrt14)/2 = -3 +- sqrt14`

NOTE
To simplify calculation, use the improved quadratic formula (Google, Yahoo Search) instead of the classical formula.
Improved formula
`D = d^2 = b^2 - 4ac`
`x = -b/(2a) +- d/(2a)`
Classical formula
`x = -b/(2a) +- (sqrt(b^2 - 4ac))/(2a)`