Question

What is 3 1/2x - 5 1/2x,x=2/5

Answer 1

`-(4)/(5)`

Explanation:

We have the following expression

`3 \;(1)/(2) x - 5\;(1)/(2)x`

and asked to evaluate this expression at
`\[x = {2\over\displaystyle 5\]`

First convert
`3 \; (1)/(2)` and
`5 \; (1)/(2)` to mixed fractions

`3 \; (1)/(2) = (3 * 2 + 1)/(2) = (7)/(2)\\`

`5 \; (1)/(2) = (5 * 2 + 1)/(2) = (11)/(2)`

Therefore

`3 \;(1)/(2) x - 5\;(1)/(2)x\\\\= (7)/(2)x - (11)/(2)x\\\\= (7 - 11)/(2) x\\\\= -(4)/(2)x \\\\= -2x\\\\`

`\mathrm{For \;x =(2)/(5)},\\\\= -2x \\= - 2 * (2)/(5)\\\\= -(4)/(5)`