Question

factorise:-
${x}^{2} + 4x - 36 = 0$
​

Answer 1

x² + 4x - 36 = 0

if you are a student of class 10 then ,

as we know that ,

a = 1 b = 4 c = - 36

now we can use formula of D = b² - 4ac

= ( 4 )² - 4 ( 1 ) ( - 36 )

= 16 + 144

= 160

√D = √160

√D = 4√10

$\alpha = \frac{ - b + \sqrt{d} }{2a} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \beta = \frac{ - b - \sqrt{d} }{2a} \\ \\ \alpha = \frac{ - 4 + 4 \sqrt{10} }{2 \times 1} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \beta = \frac{ - 4 - 4 \sqrt{10} }{2 \times 1} \\ \alpha = \frac{ 2( - 2 + 2 \sqrt{10}) }{2} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \beta = \frac{ 2( - 2 - 2 \sqrt{10} )}{2} \\ \\ \alpha = - 2 + 2 \sqrt{10} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \beta = - 2 - 2 \sqrt{10}$

I hope this will be help you

Answer 2

x^2+4x-36= 9
= x^2-4x+9x-36
= x(x+4)-9(x+4)
= (x-4) (x+9)
Ok