求初一几道代数式去括号运算.请保证全对.一、去括号计算5a-(2a-4b)2xˆ2+3(2x-xˆ2)-2(-xˆ2+3x)3xˆ2-[xˆ2+2(xy-2yˆ2)+4yˆ2]+2xya-(-b-c+d)a-(b-c+d)3a-2(b-3c)(8x-5y)-(4x-9y)-3aˆ3-[2xˆ2-(5x+1)]

Question

求初一几道代数式去括号运算.请保证全对.
一、去括号计算
<1>5a-(2a-4b)
<2>2xˆ2+3(2x-xˆ2)-2(-xˆ2+3x)
<3>3xˆ2-[xˆ2+2(xy-2yˆ2)+4yˆ2]+2xy
<4>a-(-b-c+d)
<5>a-(b-c+d)
<6>3a-2(b-3c)
<7>(8x-5y)-(4x-9y)
<8>-3aˆ3-[2xˆ2-(5x+1)]
<9>4x-(-5x+3x-6)
<10>(2m-3)+m-(3m-2)
<11>3(4x-2y)-3(-y+8x)
<12>3aˆ2-2[2aˆ2-(2ab-aˆ2)+4ab]
<13>2a+(5a-3b)-(a+2b)
<14>-3+(-xˆ2+4x)-(-8+3xˆ2)
<15>9aˆ2+[7aˆ2-(2a-aˆ2)-3a]
<16>-0.5(4xy-8xˆ2yˆ2)+1/3(xy-6xˆ2yˆ2)

Answer 1

<1>5a-(2a-4b)=5a-2a+4b=3a+4b
<2>2xˆ2+3(2x-xˆ2)-2(-xˆ2+3x)=2x²+6x-3x²+2x²-6x=x²
<3>3xˆ2-[xˆ2+2(xy-2yˆ2)+4yˆ2]+2xy=3x²-x²-2xy+4y²-4y²+2xy=2x²
<4>a-(-b-c+d)=a+b+c-d
<5>a-(b-c+d)=a-b+c-d
<6>3a-2(b-3c)=3a-2b+6c
<7>(8x-5y)-(4x-9y)=8x-5y-4x+9y=4x+4y
<8>-3aˆ3-[2xˆ2-(5x+1)]=-3a³-2x²+5x+1
<9>4x-(-5x+3x-6)=4x+5x-3x+6=6x+6
<10>(2m-3)+m-(3m-2)=2m-3+m-3m+2=-1
<11>3(4x-2y)-3(-y+8x)=12x-6y+3y-24x=-12x-3y
<12>3aˆ2-2[2aˆ2-(2ab-aˆ2)+4ab]
=3a²-2(2a²-2ab+a²+4ab)=3a²-2(3a²+2ab)=3a²-6a²-4ab=-3a²-4ab
<13>2a+(5a-3b)-(a+2b)=2a+5a-3b-a-2b=6a-5b
<14>-3+(-xˆ2+4x)-(-8+3xˆ2)=-3-x²+4x+8-3x²=-4x²+4x+5
<15>9aˆ2+[7aˆ2-(2a-aˆ2)-3a]=9a²+7a²-2a+a²-3a=16a²-5a
<16>-0.5(4xy-8xˆ2yˆ2)+1/3(xy-6xˆ2yˆ2)=-2xy+4x²y²+1/3xy-2x²y²=2x²y²-5/3xy