a x 89 + a x 12 + a x 9 = 715
a x ( 89 + 12 + 9 ) = 715
a x 110 = 715
==> a = 6,5 Tk mk,mk k lại!!!!!!!!!!!!!!!!!
a*89+a*12+a*9=715
a*(89+12+9)=715
a*110=715
a=715:110
a=6,5
\(a\times89+a\times12+a\times9=715\)
\(a\times\left(89+12+9\right)=715\)
\(a\times110=715\)
\(a=715:110\)
\(a=6,5\)
Vậy \(a=6,5\)
a x 89 + a x 12 + a x 9 = 715
a x ( 89 + 12 + 9 ) = 715
a x 110 = 715
==> a = 6,5
