1/ (5x-4)² -49x²
2/ (2x+5)² -(x-9)²
3/ x²-2xy+y²-4m²+4mn-n²
4/ 2xy+3z+6y+xz
5/ 5x²+5xy-x-y
6/ x²-xy+x+y
7/ 2x²-2xy-7x-7y
8/ x²-3x+xy-3y
9/ x²+2x+1-16y²
1/ (5x-4)² -49x²
2/ (2x+5)² -(x-9)²
3/ x²-2xy+y²-4m²+4mn-n²
4/ 2xy+3z+6y+xz
5/ 5x²+5xy-x-y
6/ x²-xy+x+y
7/ 2x²-2xy-7x-7y
8/ x²-3x+xy-3y
9/ x²+2x+1-16y²
Đáp án:
Giải thích các bước giải:
1/ (5x-4)²-49x²
=(5x-4)²-(7x)²
=(5x-4-7x)(5x-4+7x)
=(-2x-4)(12x-4)
=-8(x+2)(3x-1)
2/ (2x+5)² -(x-9)²
=(2x+5-x+9)(2x+5+x-9)
=(x-4)(3x-4)
3/x²-2xy+y²-4m²+4mn-n²
=(x²-2xy+y²)-(4m²-4mn+n²)
=(x-y)²-(2m-n)²
=(x-y-2m+n)(x-y+2m-n)
4/2xy+3z+6y+xz
=(2xy+6y)+(xz+3z)
=2y(x+3)+z(x+3)
=(x+3)(2y+z)
5/5x²+5xy-x-y
=(5x²+5xy)-(x+y)
=5x(x+y)-(x+y)
=(x+y)(5x-1)
8/x²-3x+xy-3y
=(x²+xy)-(3x+3y)
=x(x+y)-3(x+y)
=(x+y)(x-3)
9/x²+2x+1-16y²
=(x²+2x+1)-(4y)²
=(x+1)²-(4y)²
=(x+1-4y)(x+1+4y)
câu 6,7 có sai đề không bạn
Đáp án:
Giải thích các bước giải:
6/ x² – xy + x+ y
= (x² – x ) + (- xy + y )
= x ( x + 1) + y ( -x + 1)
= x ( x+1) – y (x+1)
= (x+1)(x-y)