Question

Solve the quadratic equation with completing the square method.
Xsquare+X-20=0

Answer 1

Take -20 to the RHS and then add the square of coefficient of x × 1/2 then solve

Answer 2

very easy

first shift the -20 right hand side you will get

${x}^{2} + x = 20$

then find the third term

third term =

${( \frac{1}{2} +coeficient \: of \: x) }^{2}$

you will get

${( \frac{1}{2} + 1) }^{2}$

solve it you will get the third term as

$\frac{1}{4}$

now add the third term on both sides you will get

${x}^{2} + x + \frac{1}{4 } = 20 + \frac{1}{4}$

now solve you will get

${(x + \frac{1}{2}) }^{2} = \frac{81}{4}$

then take square roots on both side you get

$x + \frac{1}{2} = + - \frac{9}{2}$

so solve further

you will get

$x = 4 \: \: \: x = - 4$

hope you get it