Question

What is `x` in the equation `-3.1(2x + 5) = -5.7 - 1.3x`?

Answer 1

`x=-2`

Explanation:

distribute the bracket on the left side of the equation.

`rArr-6.2x-15.5=-5.7-1.3x`

collect terms in x on the left side and numeric values on the right side.

add 1.3x to both sides.

`-6.2x+1.3x-15.5=-5.7cancel(-1.3x)cancel(+1.3x)`

`rArr-4.9x-15.5=-5.7`

add 15.5 to both sides.

`-4.9xcancel(-15.5)cancel(+15.5)=-5.7+15.5`

`rArr-4.9x=9.8`

To solve for x, divide both sides by - 4.9

`(cancel(-4.9) x)/cancel(-4.9)=9.8/(-4.9)`

`rArrx=-2`

`color(blue)"As a check"`

Substitute this value into the equation and if the left side equals the right side then it is the solution.

`"left side "=-3.1(-4+5)=-3.1`

`"right side "=-5.7-(-2.6)=-5.7+2.6=-3.1`

`rArrx=-2" is the solution"`