Hey there!!
Equation Given : x + 3x - 36
In order to solve this, we will need to combine the like terms.
What are like terms?
Like terms are terms which have the same variable, in the equation given, the variable mentioned is x and hence, the like terms are x and 3x.
Now, we will need to combine x and 3x.
Let's take x as 1x and 3x as 3x.
Now, we will need to add both these like terms.
1x + 3x
x will be common, we will need to add 1 and 3
1 + 3 is 4 and hence, 1x + 3x = 4x
Hence, the final equation would be :
4x - 36
Hence, the answer is option ( c )
Hope my answer helps!