Bài 1:
`a)`
`A=(4x+3y)(4x-3y)-16x²+10y²-3xy`
`=16x²-9y²-16x²+10y²-3xy`
`=(16x²-16x²)+(-9y²+10y²)-3xy`
`=y²-3xy`
`B=(2x+1)²+(x-1)(x+1)-(3x-5)²`
`=4x²+4x+1+x²-1-(9x²-30x+25)`
`=4x²+4x+1+x²-1-9x²+30x-25`
`=(4x²+x²-9x²)+(4x+30x)+(1-1-25)`
`=-4x²+34x-25`
`C=(x-2)(x²+2x+4)-(3x+1)²+(x-2)²`
`=x³-8-(9x²+6x+1)+x²-4x+4`
`=x³-8-9x²-6x-1+x²-4x+4`
`=x³+(-9x²+x²)-(6x+4x)+(-8-1+4)`
`=x³-8x²-10x-5`
`D=2xy(x²-xy+2y²)-(x+y)(x²+2xy+y²)`
`=2x³y-2x²y²+4xy³-(x+y)(x+y)²`
`=2x³y-2x²y²+4xy³-(x+y)³`
`=2x³y-2x²y²+4xy³-(x³+3x²y+3xy²+y³)`
`=2x³y-2x²y²+4xy³-x³-3x²y-3xy²-y³`
Bài 2:
`a)37.63`
`=(50-13)(50+13)`
`=50²-13²`
`=2` `500-169`
`=2` `331`
`b)1002²`
`=(1000+2)²`
`=1` `000²+2.1` `000.2+2²`
`=1` `000` `000+4` `000+4`
`=1` `004` `004`
`c)599²`
`=(600-1)²`
`=600²-2.600.1+1²`
`=360` `000-1` `200+1`
`=358` `801`
`d)550²`
`=(500+50)²`
`=500²+2.500.50+50²`
`=250` `000+50` `000+2` `500`
`=302` `500`
