Question

How do you solve `1.2x + 1 = 9`?

Answer 1

Process shown below

Explanation:

`1.2x+1=9`

Add `" -1"` on both sides

`1.2x+1-1=9-1`

`1.2x+0=8`

`1.2x=8`

`12/10x=8`

multiply 10 on both sides

`(12x)/10xx10=8xx10`

`12x=80`

divide with 12 on both sides

`(12x)xx1/12=80/12`

`x=80/12`

`x=20/3`

Answer 2

`x=6.666...`

Explanation:

Here x is the unknown variable, whose value is to be found. We take the '1' to the right hand side [You can also think of subtracting both sides by 1 - it's the same thing here], so the equation becomes,

`1.2*x=9-1=8`

Now taking the `1.2` to the right hand side [You can think of dividing both sides by `1.2` ], we get:

`x = 8/1.2 = 6.66...` which is 6.67 when rounded off to two decimal places.

Note: if you need the answer in the form of a fraction, then in the last step where `x=8/1.2`, multiply the numerator and the denominator by 10 [so that you get rid of the decimal point] and simplify to the simplest form by dividing the numerator and denominator by 4. Then, `x=(8*10) / (1.2*10) = 80/12 = (80/4)/(12/4) = 20/3`