Toán Lớp 8: rút gọn biểu thức a,3x ² – 2x.(5+1,5x)+10 b, 7x(4y – x) +4y.(y – 7x) – 2.(2y ² – 3,5x) c, (x-2).(x+2) – (x – 3).(x+1) d, x. (x – 4).(x

Toán Lớp 8: rút gọn biểu thức
a,3x ² – 2x.(5+1,5x)+10
b, 7x(4y – x) +4y.(y – 7x) – 2.(2y ² – 3,5x)
c, (x-2).(x+2) – (x – 3).(x+1)
d, x. (x – 4).(x+4) – (x ²+1). (x ² – 1)
e, (y – 3).(y+3).(y ²+9) – (y²+2). (y ² – 2)
f, (a+b+c)² – (a – c) ² – 2ab+2ab