若|3a+b+5|+|2a-2b-2|=0,則2a的平方-3ab的值為___

若|3a+b+5|+|2a-2b-2|=0,則2a的平方-3ab的值為___

|3a+b+5|+|2a-2b-2|=0
3a+b+5=0
2a-2b-2=0
a=-1
b=-2
2a的平方-3ab
=2*(-1)^2-3*(-1)*(-2)
=2-6
=-4

規定一種新運算:a*b=a+b,a@b=a-b,其中a、b為有理數,化簡a^2b*3ab+5a^2b@4ab,並求出當a=5,b=3時的值是多 少

a^2b*3ab+5a^2b@4ab
=a^2b+3ab+5a^2b-4ab,
=6a^2b-ab
=ab(6a-1)
=5*3*(6*5-1)
=435