[tex]\frac{3}{4}[/tex] is added to x, and the result is [tex]\frac{9}{8}[/tex]
To find x, you have to subtract the result by the fraction you added with x.
[tex]\frac{9}{8} - \frac{3}{4}[/tex]
The denominators aren't the same. The LCM of 4 and 8 is 8, so change the fractions so that they both have a denominator of 8.
[tex]\frac{9 \times 1}{8 \times 1} = \frac{9}{8}[/tex]
[tex]\frac{3 \times 2}{ 4 \times 2} = \frac{6}{8}[/tex]
Your new equation is:
[tex]\frac{9}{8} - \frac{6}{8} [/tex]
Subtract:
[tex]\frac{9}{8} - \frac{6}{8} = \frac{3}{8}[/tex]
ANSWER: [tex]\frac{3}{8}[/tex]
