7z+001+7z+002怎么合并

贾沫山2824已知{4x - 3y - 6z=0 x+2y - 7z=0,并且z≠0 (1)求x:y (2)求x:y:z -
邢界之15674983730 ______ (1)4x-3y-6z=0① x+2y-7z=0② ①*7-②*6→22x-33y=0 所以x:y=3:2(2) x=3y/2③ 代入②中3y/2+2y-7z=07y/2=7z z=y/2④ 所以x:y:z=3y/2:y:y/2=3/2:1:1/2=3:2:1(3) x=3z,y=2z 代入2x²+3y²+6z²)\(x²+5y²+7z²)中 则原式=[2*(3z)²+3*(2z)²+6z²]/[(3z)²+5*(2z)²+7z²] =36z²/36z² =1

贾沫山2824已知4x - 3y - 6z=0,x+2y - 7z=0,求2x+3y+6z除以x+5y+7z的值 -
邢界之15674983730 ______ 解:已知4x-3y-6z=0,x+2y-7z=0 得4x-3y=6z (1) x+2y=7z (2) (1)*2+(2)*3得 (4x-3y)*2+(x+2y)*3=6z*2+7z*38x-6y+3x+6y=12z+21z11x=33z x=33z÷11 x=3z 将x=3z带入(2)得3z+2y=7z2y=7z-3z2y=4z y=4z÷2 y=2z 即x=3z,y=2z 得(2x+3y+6z)÷(x+5y+7z)=(2*3z+3*2z+6z)÷(3z+5*2z+7z)=(6z+6z+6z)÷(3z+10z+7z)=18z÷20z=10分之9 即(2x+3y+6z)÷(x+5y+7z)=10分之9

贾沫山2824已知4x - 3y - 6z=0,x+2y - 7z=0(xyz≠0),那么2x²+3y²+6z²/x²+5y²+7z²的值为 -
邢界之15674983730 ______ 解:由4x-3y-6z=0,x+2y-7z=0 得:11y-22z=0 即y=2z......(1) 代入x+2y-7z=0,得:X=3Z........(2) 由(1),(2)有:2x²+3y²+6z²=2*(3Z)^2+3*(2Z)^2+6Z^2=36*Z^2,x²+5y²+7z²=(3Z)^2+5*(2Z)^2+7Z^2=36*Z^2 所以(2x²+3y²+6z²)/(x²+5y²+7z²)=(36*Z^2)/(36*Z^2)=1 其中＂ Z^2 ＂表示＂Z的平方＂.

贾沫山2824知4x - 3y - 6z=0,x+2y - 7z=0,且xyz不等于0,求3x+2y+z除以x+2y+3z -
邢界之15674983730 ______ (3x+2y+z)除以(x+2y+3z)=(3x+2y-6z+7z)÷(x+2y-7z+10z)=(0+7z)÷(0+10z)=7z/10z=7/10

贾沫山2824X+2Y - 9Z=0,X - 2Y - 5Z=0(X,Y,Z不等于0),求代数式X平方 - 4Y平方+9Z平方,分之,2X平方+3Y平方+7Y平方值 -
邢界之15674983730 ______ x+2y-9z=0,——(1) x-2y-5z=0——(2) (1)+(2) 2x-14z=0 x=7z 将x=7z代入(1) 7z+2y-9z=0 y=z (2x^2+3y^2+7z^2)/(x^2-4y^2+9z^2) =[2(7z)^2+3(z)^2+7z^2]/[(7z)^2-4(z)^2+9z^2] =[108z^2]/[54z^2] =2

贾沫山2824若xyz不等于0,且x+2y - 7z=0,4x - 3y - 6z=0,求(2x^2+3y^2+6z^2)除以(x^2+5y^2+7z^2)的值? -
邢界之15674983730 ______ x+2y-7z=0 (1) 4x-3y-6z=0 (2) (1)*4-(2) 11y-22z=0 y=2z x=3z 代入(2x^2+3y^2+6z^2)除以(x^2+5y^2+7z^2) =(18z^2+12z^2+6z^2)/(9z^2+20z^2+7z^2) =1

贾沫山28244x - 3y - 6z=0,x+2y - 7z=0,求2x+3y+6z/x+5y+7z的值 -
邢界之15674983730 ______ 4x-3y-6z=0 4x-3y=6z(1) x+2y-7z=0 x+2y=7z(2) 2(1)+3(2) 11x=33z x=3z 代入(2) 3z+2y=7z 2y=7z-3z=4z y=2z (2x+3y+6z)/(x+5y+7z)=(6z+6z+6z)/(3z+10z+7z)=18z/20z=18/10=9/10

贾沫山2824若2a+5b+4z=0,3a+b一7z=0,,则a+b - c的值为( ) -
邢界之15674983730 ______ 2a+5b+4z=0,①3a+b-7z=0,② ②*5-①,得13a-39z=0,a=3z.代入②,得b=-2z.∴a+b-z=0(改题了).

贾沫山2824已知4x - 3y - 6z=0和x+2y - 7z=0能组成一个方程组, -
邢界之15674983730 ______ 4x-3y-6z=0---(1) x+2y-7z=0---(2) 整理(1)(2) 4x-3y=6z---(3) x+2y=7z---(4) (3)*2+(4)*3 11x=33z x=3z (4)*4-(3) 11y=22z y=2z 3xy+yz+4zx ————————————— =(18z^2+2z^2+12z^2)/(18z^2+4z^2+8z^2)=16/152x的平方+y的平方+8z的平方

贾沫山2824若3x 5y 6=0,3x y - 7z=0则x+y+z的值是多少?若3x +5y+ 6=0,3x+ y - 7z=0则x+y+z的值是多少? -
邢界之15674983730 ______[答案] 3x +5y+ 6=0,3x+ y-7z=0 所以3x +5y+ 6+3x+ y-7z=0 6x+6y-7z=-6 x+y=-7z/6 x+y+z=-z/6 我想问一下,你有没有写错题目