规定运算 “#”为:a#b=a*b-(a+b),计算:(1)5#8 (2)8#5(3)(6#5)#4(4)6#(5#4)

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规定运算 “#”为:a#b=a*b-(a+b),计算:(1)5#8 (2)8#5(3)(6#5)#4(4)6#(5#4)
规定运算 “#”为:a#b=a*b-(a+b),计算:(1)5#8 (2)8#5(3)(6#5)#4(4)6#(5#4)

规定运算 “#”为:a#b=a*b-(a+b),计算:(1)5#8 (2)8#5(3)(6#5)#4(4)6#(5#4)
规定运算 “#”为:a#b=a*b-(a+b),计算:(1)5#8 (2)8#5(3)(6#5)#4(4)6#(5#4)
(1):5#8=5*8-(5+8)
=40-13
=27
(2):8#5
=8*5-(8+5)
=40-13
27
(3):(6#5)#4
=[6*5-(6+5)]#4
=(30-11)#4
=19#4
=19*4-(19+4)
=76-23
=53
(4)和(3)一样

a#b
=a*b-(a+b)
=a*b-a-b+1-1
=(a-1)*(b-1)-1
所以原式=(a-1)*(b-1)-1
(1):5#8=5*8-(5+8)
=4*7-1
=27
(2):8#5
=7*4-1
=27
(3):(6#5)#4
=(5*4-1)#4
=19#4
=18*3-1
=53
(4):6#(5#4)
=6#(4*3-1)
=6#11
=5*10-1
=49