Question

[Hà Thị Phương Linh]

rút gọn các biểu thức sau:

a)5x^2(3x^2-7x+2)-15x(x-3)

b)2/3xy(2x^2y-3xy+y^2)-2/3xy^3

c) (x+3)(x-3)-(x-2)(x+1)

d) (2x+1)^2+(4x-1)^2+2(2x+1)(4x-1)

e) (2x^2-3x)(5x^2-2x+1)-10x(x+3)

Answer 1

[nguyễn phương trang]

a) 5x² ( 3x² -7x+2)-15x(x-3)

=15x⁴-35x³+10x²-15x²+45x

=15x⁴-35x³-5x²+45x

c) (x+3)(x-3)(x-2)(x+1)

=(x²-9)(x²+x-2x-2)

=(x²-9)(x²-x-2)

=x⁴-x³-2x²-9x²+9x+18

=x⁴-x³-11x²+9x+18

d)(2x+1)²+(4x-1)²+2(2x+1)(4x+1)

=2x²+4x+1-16x²-8x+1

=2x²+4x+1-16x²-8x+1+16x²-4x+8x-2

=2x²+7

e) (2x²-3x)(5x²-2x+1)-10x²(x+3)

=10x⁴ -4x³+2x²-15x³+6x²-3 -10x²-30x

=10x⁴-19x³-2x²-30x-3

Answer 2

[Hà Thị Phương Linh]

thanks bn nka