Question

using (x+4) (x+b) =x^2+(ab) x+ab find (b) (4x+5) (4x+1) (c) (xy-3) (xy-5)

Answer 1

☆ (4x+5)(4x+1)

=(4x)^2+(5+1)×4x + 5×1

=16x^2+24x+5

☆ (xy-3) (xy-5)

=(xy)^2 + {-3+(-5)} ×xy + (-3×-5)

=x^2y^2 + (-8)×xy + 15

=x^2y^2 -8xy + 15

Answer 2

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

 

=(4x)^2+(5+1)×4x + 5×1

=16x^2+24x+5

(xy-3) (xy-5)

=(xy)^2 + {-3+(-5)} ×xy + (-3×-5)

=x^2y^2 + (-8)×xy + 15

=x^2y^2 -8xy + 15