what is x in this problem. 3(x + 5) = 4x?

distribute 3 first
3(x + 5) = 4x
3x+15=4x

transpose 3x to the left hand side so that you can isolate x
15=4x-3x
x=15

to check:
substitute the value of x to the original equation
3(15+5)=4(15)
3(20)=60
60=60

hope this helps

3(x + 5) = 4x
3*x + 3*5 = 4x
3x + 15 = 4x
3x - 4x = -15
-x = -15
x = -15/-1
x = 15

Step 1) 3x+15=4x
step 2) 15=4x-3x
step 3) 15=x

3(x+5)=4x open the brackets by multiplying by 3.
3x+15=4x take "3x" to the other side making it negative.
15=4x-3x subtract.
15=x

x=15

3(x+5)=4x
3x+15=4x

3x+15=4x
-3x+15=4x which equals 15= x
Your answer is 15