三道因式分解题和一道化简题x²-21xy+98y²+x-7yx的三次方-6x²+11x-6x的四次方+x的三次方-3x²-4x-4

三道因式分解题和一道化简题

x²-21xy+98y²+x-7y

x的三次方-6x²+11x-6

x的四次方+x的三次方-3x²-4x-4

x²-21xy+98y²+x-7y
=(x-7y)(x-14y)+x-7y
=(x-7y)(x-14y+1)
x的三次方-6x²+11x-6
=x³-6x²+5x+6x-6
=x(x²-6x+5)+6(x-1)
=x(x-1)(x-5)+6(x-1)
=(x-1)(x²-5x+6)
=(x-1)(x-2)(x-3)
x的四次方+x的三次方-3x²-4x-4
=x的四次方+x³+x²-4x²-4x-4
=x²(x²+x+1)-4(x²+x+1)
=(x²+x+1)(x²-4)
=(x-2)(x+2)(x²+x+1)
[√a+(a-b)/(√a+√b)](√a-√b)-(√a-3√b)√a
=a-√ab+(a-b)(√a-√b)²/[(√a+√b)(√a-√b)]-a+3√ab
=2√ab+(a-b)(a-2√ab+b)/(a-b)
=2√ab+a-2√ab+b
=a+b