x+2y-1=0
∴x+2y=1
3的2x方*81的y次方-8
=3的2x次方×3的4y次方-8
=3的(2x+4y)次方-8
=[3的(x+2y)次方]²-8
=3²-8
=1
x+2y-1=0
x+2y=1
3的2x方*81的y次方-8
=9^x*9^2y-8
=9(x+2y)-8
=9-8
=1
∵x+2y-1=0
∴x+2y=1
3^2x×81^y-8
=3^2x×3^4y-8
=3^(2x+4y)-8
=3^2-8
=9-8
=1
3的2x方*81的y次方-8=3的(2x+4y)次方-8,因为x+2y=1,所以2x+4y=2,所以原式等于3的平方-8=9-8=1
二元一次方程,有无数个答案
拿笔去算等等!