Question

What’s the value of x in the equation 3x - y = 18 when y = 27

Answer 1

You would have to insert the number into the variable. For example,
$3x - 27 = 18$
Then, you would isolate the x value (3x).
$3x = 18 + 27$
Simplify.
$3x = 45$
Finally, divide both sides by the coefficient.
$\frac{ 45}{3} = \frac{3x}{3}$
You end up with
$x = 15$

Answer 2

Firstly, we substitute y by 27 to form this equation:

3x - 27 = 18

Equation step-by-step:

3x = -27 = 18 → we take -27 to the right side of the equation

3x = 18 + 27 → we solve for 18 + 27

3x = 45 → we take 3 to the right side of the equation

x = 45 / 3 → we solve for 45 / 3

x = 15 → final answer

Hope it helped,

BioTeacher101