Question

x*x+5x-36 factorise it​

Answer 1

Answer:

(x-4)(x+6)

Step-by-step explanation:

x*x + 6x - 4x -36

x( x + 6) -4(x+6)

(x-4)(x+6)

Answer 2

$\sf\huge\bold{\underline{\underline{{Solution}}}}$

How to factorise ??

x²+5x-36

The coefficient of x² is 1

5x is a middle term and its coefficient is 5.

and the constant" is -36

Step-1 : Multiply the coefficient of x² by the constant -36×1=-36

Step-2 : Find two factors of -36 whose subtraction is equal to the coefficient of the middle term, which is 5.

There are only two possible numbers which makes :9×4 =36 and 9-4=5

=>x²+5x-36

=>x²+9x-4x-36

=>x(x+9)-4(x+9)

=>(x-4)(x+9)

x-4=0

x= 4

x+9=0

x=-9

∴Roots are x= 4 & x= -9

Alternative Method :

x²+5x-36

Here, a= 1 ,b=5 & c=-36

X=-b±√b²-4ac/2a

=>x=-5±√(5)²-4(1)(-36)/2

=>x=-5±√25+144/2

=>x=-5±√169/2

=>x=-5±13/2

x=-5±13/2

x= 8/2=4

x=4

Now , taking -ve value of x

x=-5-13/2

x=-18/2=-9

x=-9