8,75 x X + 1,25 x X = 20
\(\Rightarrow\) (8,75+1,25) x X = 20
\(\Rightarrow\) 10 x X = 20
\(\Rightarrow\) X = 20 : 10
X = 2
999 - 888 - 111 + 111 - 111 + 111 - 111
= 111 - 111 + 111 - 111 + 111 - 111
= 0 + 111 - 111 + 111 - 111
= 111 - 111 + 111 - 111
= 0 + 111 - 111
= 111 - 111
= 0
8,75 * x + 1,25 * x =20
(8,75+1,25) *x +20
10* x =20
x=2
chúc chị học tốt!!! :)
8,72*X+1,25*X=20
=X(8,75+1,25)=20
=X*10=20
=X=20:10=2
Vậy X=2