Question

Which are the solutions of the quadratic equation?
x2 = 7x + 4

Answer 1

Explanation:

`x {}^(2) = 7x + 4`

It can also be written as:-

`x {}^(2) - 7x - 4 = 0`

Now, here a=1, b= -7 and c = -4

Now by quadratic formula,

`d = b {}^(2) - 4ac`

Calculate d which is

`√(65)`

Now, the roots will be:-

`x = ( - b + √(d) ) / 2a`

and hence it will become:-

`x = (7 + √(65) ) / 2`

and

`x = (7 - √(65) ) / 2`

Answer 2

Answer: third option.

Explanation:

Move the
`7x` and
`4` to the left side of the equation:

`x^2 = 7x+ 4`

`x^2 -7x- 4=0`

Now you need to apply the Quadratic formula:

`x=(-b\±√(b^2-4ac) )/(2a)`

In this case you can identify that:

`a=1\\b=-7\\c=-4`

Then you can substitute values into the Quadratic formula and get the following solutions:

`x=(-(-7)\±√((-7)^2-4(1)(-4)) )/(2*1)\\\\x_1=(7-√(65) )/(2)\\\\x_2=(7+√(65) )/(2)`