Question

Solve the all questions and i will mark you as brainlist!☺️​

Answer 1

• (x+3)(x-4)

Expand

(x+3)(x−4)

=>x(x-4)+3(x-4)

=>x²-4x+3x-12

=>x²-x-12

• (2x+1)(2x-1)

By using identinty,

(a+b)(a-b)=a²-b²

=>(2x)²-(1)²

=>4x²-1

• (2x+5)(5-2x)

(5+2x)(5-2x)

By using identinty,

(a+b)(a-b)=a²-b²

=>(5)²-(2x)²

=>25-4x²

=>-4x²+25

• (4x-5)(4x-7)

Expand

(4x-5)(4x-7)

=>4x(4x-7)-5(4x-7)

=>(4x)²-28x-20x+35

=>16x²-48x+35

Hope it helps you ☺️,

Please mark me as brainlist .

Answer 2

1. (x+3) (x-4)= ( x*x-4*x) + ( 3x-12)

                     = x^2-4x+3x-12

                        = x^2-1x-12

2. ( 2x+1) (2x-1)=

[ here use (a+b)(a-b)= a^2-b^2],so

=> a=  2x

=> b= 1

=> a^2= 4x^2

=> b^2= 1

a^2-b^2= 4x^2-1

3. (2x+5)(5-2x)= (2x*5-4x^2)+(25-10x)

                      = 10x-4x^2+25-10x

                      = -4x^2+25

4. (4x-5)(4x-7)=( 4x*4x-7*4x)+(-20x-35)

                        = 16x^2-28x-20x-35

                         = 16x^2-48x-35