作业帮去括号 (5a+b)+6a 5-(7-6m) (2x-7)-(4x-5) (3a方-3a-1)-(5a方+6a-8) (8mm-3m方）-5mm-2(3mn-2m方) 先化简再求值 3y方-x方+(x方-y)-(x方+3y方）,x=1.y=-2
来源：学生作业帮助网 编辑：作业帮 时间：2024/11/20 19:43:10
去括号 (5a+b)+6a 5-(7-6m) (2x-7)-(4x-5) (3a方-3a-1)-(5a方+6a-8) (8mm-3m方）-5mm-2(3mn-2m方) 先化简再求值 3y方-x方+(x方-y)-(x方+3y方）,x=1.y=-2
去括号 (5a+b)+6a 5-(7-6m) (2x-7)-(4x-5) (3a方-3a-1)-(5a方+6a-8) (8mm-3m方）-5mm-2(3mn-2m方) 先化简
再求值 3y方-x方+(x方-y)-(x方+3y方）,x=1.y=-2
去括号 (5a+b)+6a 5-(7-6m) (2x-7)-(4x-5) (3a方-3a-1)-(5a方+6a-8) (8mm-3m方）-5mm-2(3mn-2m方) 先化简再求值 3y方-x方+(x方-y)-(x方+3y方）,x=1.y=-2
(5a+b)+6a
=5a+b+6a
=11a+b
5-(7-6m)
=5-7+6m
=6m-2
(2x-7)-(4x-5)
=2x-7-4x+5
=-2x-2
(3a²-3a-1)-(5a²+6a-8)
=3a²-3a-1-5a²-6a+8
=-2a²-9a+7
(8mm-3m²)-5mm-2(3mn-2m²)
=8mm-3m²-5mm-6mn+4m²
=m²-3mm
3y²-x²+(x²-y)-(x²+3y²)
=3y²-x²+x²-y-x²-3y²
=-y-x²
=2-1
=1
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(5a+b)+6a
=5a+b+6a
=11a+b
5-(7-6m)
=5-7+6m
=6m-2
(2x-7)-(4x-5)
=2x-7-4x+5
=-2x-2
(3a²-3a-1)-(5a²+6a-8)
=3a²-3a-1-5a²-6a+8
=-2a²...
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(5a+b)+6a
=5a+b+6a
=11a+b
5-(7-6m)
=5-7+6m
=6m-2
(2x-7)-(4x-5)
=2x-7-4x+5
=-2x-2
(3a²-3a-1)-(5a²+6a-8)
=3a²-3a-1-5a²-6a+8
=-2a²-9a+7
(8mm-3m²)-5mm-2(3mn-2m²)
=8mm-3m²-5mm-6mn+4m²
=m²-3mm
3y²-x²+(x²-y)-(x²+3y²)
=3y²-x²+x²-y-x²-3y²
=-y-x²
=2-1
=1
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