已知x和y满足2x+3y=5,则当x=4时,代数式3x2+12xy+y2的值是( )
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已知x和y满足2x+3y=5,则当x=4时,代数式3x2+12xy+y2的值是( )
A. 4
B. 3
C. 2
D. 1
A. 4
B. 3
C. 2
D. 1
![已知x和y满足2x+3y=5,则当x=4时,代数式3x2+12xy+y2的值是( )](/uploads/image/z/13588471-55-1.jpg?t=%E5%B7%B2%E7%9F%A5x%E5%92%8Cy%E6%BB%A1%E8%B6%B32x%2B3y%3D5%EF%BC%8C%E5%88%99%E5%BD%93x%3D4%E6%97%B6%EF%BC%8C%E4%BB%A3%E6%95%B0%E5%BC%8F3x2%2B12xy%2By2%E7%9A%84%E5%80%BC%E6%98%AF%EF%BC%88%E3%80%80%E3%80%80%EF%BC%89)
把x=4代入2x+3y=5得:y=-1,
把x=4,y=1代入3x2+12xy+y2得:
3×16+12×4×(-1)+1=1,
故选D.
把x=4,y=1代入3x2+12xy+y2得:
3×16+12×4×(-1)+1=1,
故选D.
已知x和y满足2x+3y=5,则当x=4时,代数式3x2+12xy+y2的值是( )
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