规定a*b=4a-5b,则(6*4)*2=?,x*(2*x)=18,x=?

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规定a*b=4a-5b,则(6*4)*2=?,x*(2*x)=18,x=?

规定a*b=4a-5b,则(6*4)*2=?,x*(2*x)=18,x=?
规定a*b=4a-5b,则(6*4)*2=?,x*(2*x)=18,x=?

规定a*b=4a-5b,则(6*4)*2=?,x*(2*x)=18,x=?
6*4
=4x6-5x4
=4
(6*4)*2
=4*2
=4x4-5x2
=6
2*x
=4x2-5x
=8-5x
x*(2*x)
=x*(8-5x)
=4x-5(8-5x)
=29x-40
29x-40=18
29x=58
x=2

(6*4)*2
=﹙4×6-5×4)*2
=4*2
=4×4-5×2
=6
x*(2*x)
=x*(2×4-5x)
=4x-5(8-5x)
=18
4x-5(8-5x)=18
4x-40+25x=18
29x=58
x=2