Can someone explain me how to solve this?

x = 12

Step-by-step explanation:

There are two triangles. The two vertical lines on the legs at the top indicate that those two sides are congruent or equal to each other. The line down the middle with the right angle box shows that the two triangles share a common side. This would show the two triangles are congruent through Side/Angle/Side. This would indicate that the two sides with equations are equal to each other. That being said, you can setup the equations to equal one another to solve for x:

Now, you would just solve this like a normal equation. I would subtract the 7x from both sides a well as add the 48 to both sides. This would result to:

Dividing both sides by 6 would get you:

if you mean

then it's c. 8, -7/3

but if you mean

then it is

go and ask your mom to you