x/4+y/3=-1和5(x-8)=6(y+9)怎么解?
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x/4+y/3=-1和5(x-8)=6(y+9)怎么解?
x/4+y/3=-1和5(x-8)=6(y+9)怎么解?
x/4+y/3=-1和5(x-8)=6(y+9)怎么解?
x/4+y/3=-1
两边乘12
3x+4y=-12 (1)
5(x-8)=6(y+9)
5x-40=6y+54
5x-6y=94 (2)
(1)×3+(2)×2
9x+12y+10x-12y=-36+188
19x=152
x=8
y=(-12-3x)/4=-9
1. 把下列多项式分解因式:
(1) 3x+3y
=3(x+y)
(2) -24m^2x-16n^2x;
=-8x(m^2+2n^2)
(3) x^2-1
=(x+1)(x-1)
(4) (xy)^2-1;
=(xy+1)(xy-1)
(5) a^4x^2-a^4y^2
=a^4(x^2-y^2)
=a^...
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1. 把下列多项式分解因式:
(1) 3x+3y
=3(x+y)
(2) -24m^2x-16n^2x;
=-8x(m^2+2n^2)
(3) x^2-1
=(x+1)(x-1)
(4) (xy)^2-1;
=(xy+1)(xy-1)
(5) a^4x^2-a^4y^2
=a^4(x^2-y^2)
=a^4(x+y)(x-y)
(6) 3x^2+6xy+3y^2;
=3(x^2+2xy+y62)
=3(x+y)^2
(7) (x-y)^2+4xy
=x^2-2xy+y^2+4xy
=x^2+2xy+y^2
=(x+y)^2
(8) 4a^2-3b(4a-3b).
=4a^2-12ab+9b^2
=(2a-3b)^2
2.2x(a-2)-y(2-a)
=2x(a-2)+y(a-2)
=(a-2)(2x+y)
=(0.5-2)*(2*1.5-2)
=-1.5*1
=-1.5
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