化简代数式与求值*后面代表次方,1.x=3时,代数式ax*3 + bx + 8的值是12,求x=3时,代数式ax*3 + bx - 5的值2.若x/3 = y/4 = z/5,且4x - 5y + 2z=10,求2x- 5y +z的值3.已知a+b=3,ab=2,求a*2 + b*2的值4.若x+y=1 ,求x*3 +y*3 +3xy
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![化简代数式与求值*后面代表次方,1.x=3时,代数式ax*3 + bx + 8的值是12,求x=3时,代数式ax*3 + bx - 5的值2.若x/3 = y/4 = z/5,且4x - 5y + 2z=10,求2x- 5y +z的值3.已知a+b=3,ab=2,求a*2 + b*2的值4.若x+y=1 ,求x*3 +y*3 +3xy](/uploads/image/z/3930368-32-8.jpg?t=%E5%8C%96%E7%AE%80%E4%BB%A3%E6%95%B0%E5%BC%8F%E4%B8%8E%E6%B1%82%E5%80%BC%2A%E5%90%8E%E9%9D%A2%E4%BB%A3%E8%A1%A8%E6%AC%A1%E6%96%B9%2C1.x%3D3%E6%97%B6%2C%E4%BB%A3%E6%95%B0%E5%BC%8Fax%2A3+%2B+bx+%2B+8%E7%9A%84%E5%80%BC%E6%98%AF12%2C%E6%B1%82x%3D3%E6%97%B6%2C%E4%BB%A3%E6%95%B0%E5%BC%8Fax%2A3+%2B+bx+-+5%E7%9A%84%E5%80%BC2.%E8%8B%A5x%2F3+%3D+y%2F4+%3D+z%2F5%2C%E4%B8%944x+-+5y+%2B+2z%3D10%2C%E6%B1%822x-+5y+%2Bz%E7%9A%84%E5%80%BC3.%E5%B7%B2%E7%9F%A5a%2Bb%3D3%2Cab%3D2%2C%E6%B1%82a%2A2+%2B+b%2A2%E7%9A%84%E5%80%BC4.%E8%8B%A5x%2By%3D1+%2C%E6%B1%82x%2A3+%2By%2A3+%2B3xy)
化简代数式与求值*后面代表次方,1.x=3时,代数式ax*3 + bx + 8的值是12,求x=3时,代数式ax*3 + bx - 5的值2.若x/3 = y/4 = z/5,且4x - 5y + 2z=10,求2x- 5y +z的值3.已知a+b=3,ab=2,求a*2 + b*2的值4.若x+y=1 ,求x*3 +y*3 +3xy
化简代数式与求值
*后面代表次方,
1.x=3时,代数式ax*3 + bx + 8的值是12,求x=3时,代数式ax*3 + bx - 5的值
2.若x/3 = y/4 = z/5,且4x - 5y + 2z=10,求2x- 5y +z的值
3.已知a+b=3,ab=2,求a*2 + b*2的值
4.若x+y=1 ,求x*3 +y*3 +3xy的值
化简代数式与求值*后面代表次方,1.x=3时,代数式ax*3 + bx + 8的值是12,求x=3时,代数式ax*3 + bx - 5的值2.若x/3 = y/4 = z/5,且4x - 5y + 2z=10,求2x- 5y +z的值3.已知a+b=3,ab=2,求a*2 + b*2的值4.若x+y=1 ,求x*3 +y*3 +3xy
1.x=3时ax*3 + bx + 8=27a+3b+8=12则27a+3b=4 则x=3时,ax*3 + bx - 5=27a+3b-5=4-5=-1
2.设a=x/3 = y/4 = z/5,带入4x - 5y + 2z=10求得a=5;则2x- 5y +z=2*15-5*20+25=-45
3.a*2 + b*2=(a+b)*2-2ab=9-4=5
4.x*3 +y*3 +3xy=(x+y)*3-3xy(x+y)+3xy=1
ax*3 + bx + 8=12
ax*3 + bx =4
ax*3 + bx -5=4-5=-1
x=3z/5; y=4z/5
则12z/5-4z+2z=10
2z/5=10 z=25
x=15 y=20
a=3-b ;(3-b)b=2; 3b-b*b=2; (b-1)(b-2)=0
a=1 b=2; a=2 b=1<...
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ax*3 + bx + 8=12
ax*3 + bx =4
ax*3 + bx -5=4-5=-1
x=3z/5; y=4z/5
则12z/5-4z+2z=10
2z/5=10 z=25
x=15 y=20
a=3-b ;(3-b)b=2; 3b-b*b=2; (b-1)(b-2)=0
a=1 b=2; a=2 b=1
a*2 + b*2=1+4=5
y=1-x
x*3+(1-x)*3+3x(1-x)=x*3+(1-2x+x*2)(1-x)+3x-3(x*2)
=x*3+1-x-2x+2(x*2)+x*2-x*3+3x-3(x*2)=1
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