Algebra (Linear Equations)

1 / 1

Linear equation with two fractions

Question: Solve x4x28=5\dfrac{x}{4} - \dfrac{x-2}{8} = 5.

Step 1. Bring both fractions to the common denominator 88:

2x8x28=5\dfrac{2x}{8} - \dfrac{x-2}{8} = 5

Step 2. Combine — keeping the second numerator in a bracket:

2x(x2)8=5    2xx+28=5    x+28=5\dfrac{2x - (x-2)}{8} = 5 \;\Rightarrow\; \dfrac{2x - x + 2}{8} = 5 \;\Rightarrow\; \dfrac{x+2}{8} = 5

Step 3. Multiply up:

x+2=40x + 2 = 40

Step 4.

x=38x = 38

Check. 384368=9.54.5=5\dfrac{38}{4} - \dfrac{36}{8} = 9.5 - 4.5 = 5. ✓

(Equally valid: multiply the whole equation by 88 at the start — 2x(x2)=402x - (x-2) = 40 — same bracket, same answer.)

The same two routes (combine-first or clear-denominators-first) work on every fraction equation; pick whichever keeps the numbers smaller and carry brackets until the signs are resolved.

⚠ Watch out: The subtraction applies to the whole numerator: (x2)=x+2-(x-2) = -x + 2, not x2-x - 2 — this single sign is the most-lost mark in fraction equations. Multiply every term by the denominator, including the lonely 55 on the right.

🤖Ask