Question

15x+6=10x+21 what’s x

Answer 1

`x=3`

Explanation:

`15x+6=10x+21`

Subtract 6 from both sides:

`15x+6-6=10x+21-6`

`15x=10x+15`

Subtract 10x from both sides:

`15x-10x=10x+15-10x`

`5x=15`

Divide both sides by 5:

`(5x)/(5)=(15)/(5)`

`x=3`

Answer 2

`\boxed{ \bold{ \huge{ \boxed{ \sf{x = 3}}}}}`

Explanation:

`\sf{15x + 6 = 10x + 21}`

Move 10x to left hand side and change it's sign

Similarly, move 6 to right hand side and change it's sign

`\dashrightarrow{ \sf{15x - 10x = 21 - 6}}`

Collect like terms

`\dashrightarrow{ \sf{5x = 21 - 6}}`

Subtract 6 from 21

`\dashrightarrow{ \sf{5x = 15}}`

Divide both sides by 5

`\dashrightarrow{ \sf{ (5x)/(5) = (15)/(5)}}`

Calculate

`\dashrightarrow{ \sf{x = 3}}`

Hope I helped!

Best regards! :D