Question

Given the equation:

5x2−x−4=0





Solve using the quadratic formula

Answer 1

x = 1 and x =
`(-4)/(5)`

Explanation:

In this equation, a=5, b=-1, c=-4.

Plug these into the quadratic formula:

x =
`\frac{1+\sqrt{-1^(2)-(-4)(5)(-4) } }{2(5)}` and x =
`\frac{1-\sqrt{-1^(2)-(-4)(5)(-4) } }{2(5)}`

Now, simplify the equations:

x =
`(1+√(81) )/(10)` =
`(1+9)/(10)` =
`(10)/(10)` = 1

and

x =
`(1-√(81) )/(10)` =
`(1-9)/(10)` =
`(-8)/(10)` =
`(-4)/(5)`