Question

Factorise =2x²-2x-40 ​

Answer 1

Answer:

${2x}^{2} - 2x - 40 \\ \\ = 2( {x}^{2} - x - 20) \\ \\ = {x}^{2} - x - 20 \\ \\ = {x}^{2} - (5 - 4)x - 20 \\ \\ = {x}^{2} - 5x + 4x - 20 \\ \\ = x( x - 5) + 4(x - 5) \\ \\ = (x - 5)(x + 4)$

✔✔✔done ✔✔✔

Answer 2

Given :

• 2x²-2x-40

To find :

• Factorise

Solution :

=> 2x² - 2x - 40 = 0

=> x² - x - 40 = 0

=> x² - 5x - 4x - 40 = 0

=> x(x - 5) - 4 ( x - 5) = 0

=> (x - 4) (x - 5) = 0

=> x - 4 = 0 or x - 5 = 0

=> x = 4 or x = 5

∴ value of x is 4 and 5

Extra information :

• Volume of cylinder = πr²h

• T.S.A of cylinder = 2πrh + 2πr²

• Volume of cone = ⅓ πr²h

• C.S.A of cone = πrl

• T.S.A of cone = πrl + πr²

• Volume of cuboid = l × b × h

• C.S.A of cuboid = 2(l + b)h

• T.S.A of cuboid = 2(lb + bh + lh)