Toán Lớp 7: a) M+(5x²-2xy)=6x²+9xy-y² b) M-(3xy-4y²)=x²-7xy+8y² c) (25x²y-13xy²+y3) -M=11x²y-2y³ d) M+(12x⁴-15x²y+2xy²+7) =0 Ai giúp e vs ạ e cần g

Question

Toán Lớp 7:  a) M+(5x²-2xy)=6x²+9xy-y² b) M-(3xy-4y²)=x²-7xy+8y² c) (25x²y-13xy²+y3) -M=11x²y-2y³ d) M+(12x⁴-15x²y+2xy²+7) =0 Ai giúp e vs ạ e cần gấp trc 9h15 :((

lyly98 · Answer

Giải đáp + Lời giải và giải thích chi tiết:     a)   M+(5x^{2}-2xy)=6x^{2}+9xy-y^{2}   ->M=6x^{2}+9xy-y^{2}-5x^{2}+2xy   ->M=(6x^{2}-5x^{2})-y^{2}+(9xy+2xy)   ->M=x^{2}-y^{2}+11xy   b)   M-(3xy-4y^{2})=x^{2}-7xy+8y^{2}   ->M=x^{2}-7xy+8y^{2}+3xy-4y^{2}   ->M=x^{2}+(8y^{2}-4y^{2})+(3xy-7xy)   ->M=x^{2}+4y^{2}-4xy   c)   (25x^{2}y-13xy^{2}+y^{3})-M=11x^{2}y-2y^{3}   ->M=25x^{2}y-13xy^{2}+y^{3}-(11x^{2}y-2y^{3})   ->M=(25x^{2}y-11x^{2}y)-13xy^{2}+(y^{3}+2y^{3})   ->M=14x^{2}y-13xy^{2}+3y^{3}   d)   M+(12x^{4}-15x^{2}y+2xy^{2}+7)=0   ->M=-12x^{4}+15x^{2}y-2xy^{2}-7

ankim · Answer

a)   M+(5x^2-2xy)=6x^2+9xy-y^2    to M=6x^2+9xy-y^2-5x^2+2xy    to M=(6x^2-5x^2)+(9xy+2xy)-y^2    to M=x^2+11xy-y^2   b)   M-(3xy-4y^2)=x^2-7xy+8y^2    to M-3xy+4y^2=x^2-7xy+8y^2    to M=x^2-7xy+8y^2+3xy-4y^2    to M=x^2+(-7xy+3xy)+(8y^2-4y^2)    to M=x^2-4xy+4y^2   c)   (25x^2y-13xy^2+y^3)-M=11x^2y-2y^3    to M=25x^2y-13xy^2+y^3-11x^2y+2y^3    to M=(25x^2y-11x^2y)+(y^3+2y^3)-13xy^2    to M=14x^2y+3y^3-13xy^2   d)   M+(12x^4-15x^2y+2xy^2+7)=0    to M=-12x^4+15x^2y-2xy^2-7