425,3+x=315,6×12
425,3+x=3787,2
x=3787,2-425,3
x=3361,9
vậy x=3361,9
136,5-x=5,4:1,2
136,5-x=4,5
x=136,5-4,5
x=132
vậy x=132
a)\(425,3+x=315,6×12\)
\(425,3+x=3781,2\)
\(x=3781,2-425,3\)
\(x=3355,9\)
b)\(136,5-x=5,4\div1,2\)
\(\frac{273}{2}-x=\frac{27}{5}+\frac{6}{5}\)
\(\frac{273}{2}-x=\frac{33}{5}\)
\(136,5-x=6,6\)
\(x=136,5-6,6\)
\(x=129,9\)