Answers

2015-07-05T22:49:16+08:00
1) 3x-4y
=3(-1)-4(5)
= -3-20
=-23
2) x(2x-y)
=-1[2(-1)-5]
=-1(-2-5)
=-1(-7)
=7
3) 2x-y
=2(-1)-5
=-2-5
=-7
4) (x²-3x²+2x²-1)²
=[(-1²)-3(-1²)+2(-1²)-1]²
=[(1)-3(1)+2(1)-1]²
=(1-3+2-1)²
=(-1)²
=1
5) x²y²-xy
=(-1²)(5²)-(-1)(5)
=(1)(25)-(-1)(5)
=25-(-5)
=25+5
=30
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