Đáp án:
`a. A=(3x-1)^2+(x+3)(2x-1)`
`= 9x^2-6x+1+2x^2+5x-3`
`= 11x^2-x-2`
`b. B=(x-2)(x^2+2x+4)-x(x^2-2)`
`= (x^3-8)-x^3+2x`
`= x^3-8-x^3+2x`
`= 2x-8`
`c. C=(3x-5)^2+(3x+5)^2-2(3x+5)(3x-5)`
`= [(3x-5)-(3x+5)]^2`
`= [3x-5-3x-5]^2`
`= -10^2`
`= 100`
Hay:
`c. C=(3x-5)^2+(3x+5)^2-2(3x+5)(3x-5)`
`= [(3x+5)-(3x-5)]^2`
`= [3x+5-3x+5]^2`
`= 10^2`
`= 100`