Question

How do you solve `3(x+3)=4x`?

Answer 1

`color(blue)(x=9)`

Explanation:

`3(x+3)=4x`

Using distributive property to evaluate the expression in the left side of the equation,

`3x+9=4x`

transposing `+9` to the other side of the equation, by grouping all the same expression or term, it is a standard that the unknown variable must be in the left side of the equation,

Subtracting `9` from both sides,

`3x+9-9=4x-9`

Refining the equation,

`3x=4x-9`

now we must move the `4x` to the left, balance it by subtracting both sides by `4x`,

`3x-4x=4x-9-4x`

Refining the equation again, we get,

`-x=-9`

but, `x`, the unknown variable must be positive, therefore we need to take off it's negativity, since `-x = -1(x)`

`cancel(-x)/cancel(-1)=(-9)/-1`

therefore, the answer is,

`color(blue)(x=9)`