=(3x-5)(3x-5)-(2x+7)(2x+7)

=9x？ -30x+25-4x？ +28x+49

=5x？ -2x+74

Solution: (2)(x+y+ 1)(x+y- 1)

=[(x+y)+ 1][(x+y)- 1]

=(x+y)？ - 1?

=x？ +2xy+y？ - 1

Solution: (3)(2x-y-3)?

=[(2x-y)-3]？

=(2x-y)？ -6(2x-y)+9

=4x？ -4xy+y？ - 12x+6y+9

Solution: (4)[(x+2)(x-2)]?

=(x？ -4)?

=(x？ -4)(x？ -4)

=x？ -8x？ + 16

Question 4: Solution: (2x+3y)? -(2x+y)(2x-y)

=4x？ + 12xy+9y？ -4x？ +y？

= 12xy+ 10y？

Substitute x= 1/3 and y=- 1/2 into 12xy+ 10y?

12xy+ 10y？

= 12× 1/3×(- 1/2)+ 10×(- 1/2)?

=-2+5

=3

I hope it will help you, and I hope to use ` (* ∩ _ ∩ *)'.