Question

Using the quadratic formula to solve 2
4x - 7. what are the values of x2

Answer 1

x=
`-2\pm √(11)`

Explanation:

Here is the correct question: Using the quadratic formula to solve

x²+4x - 7. what are the values of x.

Solving by using quadratic formula.

Formula:
`\frac{-b\pm \sqrt{b^(2)-4(ac) } }{2a}`

∴ In the expression
`x^(2) +4x-7`, we have a= 1, b= 4 and c= -7.

Now, subtituting the value in the formula.

=
`\frac{-4\pm \sqrt{4^(2)-4(1* -7) } }{2* 1}`

=
`\frac{-4\pm \sqrt{4^(2)-4(-7) } }{2}`

Opening parenthesis.

=
`(-4\pm √(16+28 ) )/(2* 1)`

=
`(-4\pm √(44))/(2)`

We know 2²=4

=
`\frac{-4\pm \sqrt{2^(2)* 11 }}{2}`

we know √a²=a

=
`(-4\pm 2 √(11 ))/(2)`

Taking 2 as common in the expression.

=
`(2(-2\pm √(11)) )/(2)`

Cancelling 2

=
`-2\pm √(11)`

Hence we get,
`x=-2\pm√(11)`