Nhầm giải lại :
a x \(\frac{1}{3}\)+ a x \(\frac{1}{4}\)= 21,35
a (\(\frac{1}{3}\)+\(\frac{1}{4}\)) = 21,35
a = 21,35 x \(\frac{12}{7}\)
a = 36,6
a : 3 + a : 4 = 21,35
a : ( 3 + 4 ) = 21,35
a : 7 = 21,35
a = 21,35 x 7
a = 149,45
a : (3 x 4) = 21,35
a = 21,35 x 12
a = 256,2
a:3+a:4=21,35
<=>a:(3+4)=21,35
<=>a:7=21,35
=>a=21,35 . 7
=> a= 149,45