Answer:
x=3
Step-by-step explanation:
Use pemdas!
First use distributive property to get rid of the parenthesis, by multiplying 2 by 3x and -4. Then combine like terms and use inverse operations to simplify each side until you get it down to just x! Hope this helped! :)
All the triangles are isosceles meaning that they have to sides that are equal
I hope this helps you
l=x+2
w=2x-5
(x+2)(2x-5)=56
2x^2-x-10=56
2x^2-x-66=0
2x +11
x -6
(2x+11)(x-6)=0
x=6
750+20(30)=1350
Or do you need to explain it?
Answer: 
Step-by-step explanation:
You know that the triangle ABC and the triangle DEF are similar.
Therefore, if the lenght of AC is 12 centimeters and the lenght of DF is 10 centimeters, then you can find the ratio as following:

Then, the calculte the length of EF, you must multiply the lenght BC of the triangle ABC by the ratio obtained above.
Therefore, the lenght EF is the following:
