111k views
4 votes
If 2x + 5 = 8x, then 12x = ?
A 5
B
10
C
15
D 20

User Aguayma
by
5.9k points

2 Answers

5 votes

Answer:

B. 10

Explanation:

To find 12x, you first need to find the value of x using the first equation:


2x+5=8x

You need to get the variables (x) on the same side of the equation in order to simplify them. To do this, use reverse operations. Subtract 2x from both sides to keep the equation balanced:


2x-2x+5=8x-2x\\\\5=6x

Now isolate the variable (x) by dividing both sides of the equation by 6 (using reverse operations):


(5)/(6)=(6x)/(6) \\\\(5)/(6)=x

Now insert the given value of x into 12x:


12((5)/(6))

Simplify:


12*(5)/(6) \\\\(12)/(1)*(5)/(6)\\\\(60)/(6)=10

12x equals 10.

:Done

User Jochy
by
6.0k points
3 votes

Answer:

10

Explanation:

2x + 5 = 8x

Subtract 2x from each side

2x-2x + 5 = 8x-2x

5 = 6x

We want 12x so multiply each side by 2

2*5 = 6x*2

10 = 12x

User Sachin Trivedi
by
6.5k points