Simply Each expression by using the distributive property to remove parentheses and combining like terms.
1/2x+1/4x=

You don't need to use the distributive property because there is nothing to distribute, so all you need to do is combine like terms, and they are like terms because they have the same variable to the same power/exponent which is 1.
To combine fractions (by addition or subtraction), they need to have the same denominator. To do so, you can find the least common multiple of 2 and 4, unless you already know what number 2 and 4 have in common, which is 4.
[tex]\frac{1}{2}x+\frac{1}{4}x=[/tex] Multiply [tex]\frac{1}{2}[/tex] by [tex]\frac{2}{2}[/tex] to make the denominator = 4
[tex](\frac{2}{2})\frac{1}{2}x+\frac{1}{4}x[/tex]
[tex]\frac{2}{4}x+\frac{1}{4}x[/tex] Now combine the like terms
[tex]\frac{3}{4}x[/tex]