Question

20x square +21x -5 =0 factorisation method

Answer 1

Answer:

$\huge{\boxed{\rm{\red{Roots =1/5 and -5/4}}}}$

Step-by-step explanation:

Given equation is 20x²+21x-5=0

=>20x²+25x-4x-5=0

=>20x²-4x+25x-5=0

=>4x(5x-1)+5(5x-1)=0

=>(5x-1)(4x+5)=0

(5x-1)=0 or 4x+5=0

=>5x=1

=>x=1/5

4x+5=0

=>4x=-5

=>=-5/4

Roots of the given equation are 1/5 and -5/4

Answer 2

Step-by-step explanation:

20x²+21x-5=0

Let factorise it by spilliting middle term

- 5 is smaller than 21x so we multiply (20×5=100) it for making larger than 21x

hence,

20x² + (25-4)x-5

20x²+25x-4x-5

5x(4x+5) -1(4x+5)

(5x-1) (4x+5) = 0

5x-1=0

5x=1

x = 1/5

4x+5 =0

4x=-5

x= -5/4

Roots of the equation are 1/5 and -5/4

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