Question

Q- Expand using identities:
(5x+2) (4x-1)

Answer 1

Answer:

5x(4x-1) +2 (4x-1)

20x²-5x+8x-2

20x²+3x-2x

Answer 2

• As per the data given in the question, we have to determine the value of the given expression.

       Given data:- $(5x+2)(4x+1).$

       To find:- expand the given expression.

       Solution:-

          $(x + a)(x + b) = x(x + b) + a (x + b) = x2 + xb + ax + ab = x2 + (b + a)x + ab$

• Here, we will use the above identities. we get,

        $\Rightarrow (5x+2)(4x-1)\\\Rightarrow 5x\times4x-5x\times1+2\times4x-2\times1\\\Rightarrow 20x^{2}-5x+8x-2\\\Rightarrow 20x^{2}-x(5+8)-2\\\Rightarrow 20x^{2}-13x-2.$

      Hence, the expansion will be $(5x+2)(4x-1).$