Name: Variables on both sides: solution walkthrough
Uploaded: 2026-11-13
Duration: 2 min 3 s
Description: What value of x makes the equation 5x - 4 = 2x + 8 true? Try it, then watch the animated solution.

An equation is like a balance: both sides weigh the same. Doing the same thing to both sides keeps it level.

Take

2x

off both sides, so

x

is only on the left:

5x - 4 = 2x + 8

becomes

3x - 4 = 8

.

Add

4

to both sides. On the left,

+4

cancels the

{-4}

, so

3x = 12

.

Three

x

balance twelve ones. Split both sides into

3

equal groups:

x = 12 \div 3 = 4

.

Check in the first equation:

5(4) - 4 = 16

and

2(4) + 8 = 16

. Both sides match.

Traps:

\tfrac{12}{7}

adds

2x

instead of subtracting,

\tfrac{4}{3}

subtracts the

4

, and

12

never divides by

3

.

Try it first