两题数学题(要写过程)1.先简化,再求值:(t+3t²-3)-(-t+4t²),其中t=﹣1.解:当t=﹣1时,(t+3t²-3)-(-t+4t²)=(后面怎么写?)2.化简并求值:2(x+y)-3分之2

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两题数学题(要写过程)1.先简化,再求值:(t+3t²-3)-(-t+4t²),其中t=﹣1.解:当t=﹣1时,(t+3t²-3)-(-t+4t²)=(后面怎么

两题数学题(要写过程)1.先简化,再求值:(t+3t²-3)-(-t+4t²),其中t=﹣1.解:当t=﹣1时,(t+3t²-3)-(-t+4t²)=(后面怎么写?)2.化简并求值:2(x+y)-3分之2
两题数学题(要写过程)
1.先简化,再求值:(t+3t²-3)-(-t+4t²),其中t=﹣1.
解:当t=﹣1时,
(t+3t²-3)-(-t+4t²)
=(后面怎么写?)
2.化简并求值:2(x+y)-3分之2(x-y)-3(x+y)+3分之2(x-y),其中x=﹣2,y=﹣1.

两题数学题(要写过程)1.先简化,再求值:(t+3t²-3)-(-t+4t²),其中t=﹣1.解:当t=﹣1时,(t+3t²-3)-(-t+4t²)=(后面怎么写?)2.化简并求值:2(x+y)-3分之2
先简化,再求值:(t+3t²-3)-(-t+4t²),其中t=﹣1.
当t=﹣1时,
(t+3t²-3)-(-t+4t²)
=t+3t²-3+t-4t²
=-t²+2t-3
=-1-2-3
=-6;
2.化简并求值:2(x+y)-3分之2(x-y)-3(x+y)+3分之2(x-y),其中x=﹣2,y=﹣1.
=-(x+y)+0;
=-x-y
=2+1
=3;
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