Question

I don't understand how to do this

Answer 1

Hi!
The table above is showing how to plug in a variable to x. For an example,
$5x - 3 =?$
when x= 4 would equal 17. How we would get this is substitute x with 4 and use our order of operations.
$5(4) - 3 = 20 - 3 = 17$
To get 68, we would do this in reverse. We would add 3 to both sides to eliminate the -3 to have a remainder of
$5x = 71$
Divide both sides by five to solve for x.
$x = \frac{71}{5}$
We can also check our math and plug in 17/5 into x
$5( \frac{71}{5} ) - 3 =71 - 3 = 68$