Question

factorise 2x^2+x-45 by factor theorem​

Answer 1

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

➙2x²+x-45

How to factorise ?

2x²+x-45

The coefficient of x² is 2

x is a middle term and its coefficient is 1.

and the constant" is -45

Step-1 : Multiply the coefficient of x² by the constant 45×2=90

Step-2 : Find two factors of 90 whose sum/Substract is equal to the coefficient of the middle term, which is 1.

Now, 2x²+x-45

45×2= 90

Factors of 90= 1,2,3,5,9,10,18

If we Multiply 10×9= 90

and we substract 10-9= 1

it satisfied

Factorise by middle term splitting method

➙2x²+10x-9x-45=0

➙2x(x+5)-9(x+5)

➙(2x-9)(x+5)=0

➙2x-9= 0 & x+5=0

➙x= 9/2 or x = -5

Hence , x = 9/2 & -5

Answer 2

➙2x²+10x-9x-45=0

➙2x(x+5)-9(x+5)

➙(2x-9)(x+5)=0

➙2x-9= 0 & x+5=0

➙x= 9/2 or x = -5

Hence , x = 9/2 & -5