X x 1 + X x 3 = 48
X x (1+3) = 48
X x 4 = 48
X = 48 : 4
X = 12
X + X * 3 = 48
x*1+x*3=48
x*(1+3)=48
x*4=48
x=12
\(\Rightarrow\) X x 1 + X x 3 = 48
\(\Rightarrow\) X x (1+3) = 48
\(\Rightarrow\) X x 4 = 48
\(\Rightarrow\)X = 48 : 4
\(\Rightarrow\) X = 12
X + 1 + X + 3 = 48
X x ( 1 + 3 ) = 48
X x 4 = 48
X = 48 : 4
X = 12
X + X x 3 = 48
X x 1 + X x 3 = 48
X x [ 1 + 3 ] = 48
X x 4 = 48
X = 48 : 4
X = 12
X + 1 + X + 3 = 48
X x ( 1 + 3 ) = 48
X x 4 = 48
X = 48 : 4
X = 12
X x 1 + X x 3 = 48
X x ( 1 + 3 ) = 48
X x 4 = 48
X = 48 : 4
X = 12