Question

Simplify :
1. (x - 7) (5x - 4) + 3x?
2. (x – 2y) (x + y) – 3x (4 - y)
3. (a - b) (b + a) + a (b - a + 4)​

Answer 1

Answer:

1)5x²-13x+28

2)x²+2xy-2y²-12x

3)-b²+ab+4a

Step-by-step explanation:

1) [x(5x-4)-7(5x-4)]+3x

=[5x²-4x-12x+28] +3x

=5x²-16x+28+3x

=5x²-13x+28

2) [x(x+y)-2y(x+y)]-3x(4-y)

=[x²+xy-2xy-2y²]-12x+3xy

= x²-xy-2y²-12x+3xy

= x²+2xy-2y²-12x

3) [a(b+a)-b(b+a)]+a(b-a+4)

= [ab+a²-b²-ab] + ab-a²+4a

= a²-b²+ab-a²+4a

= -b²+ab+4a