Answer:
x=2
Step-by-step explanation:
6x+11-4x=15
2x+11=15
2x=4
x=2
Answer:
8.06
Step-by-step explanation:
Use the Pythagorean theorem:

The hypotenuse is always the slanted side, or c (x in this picture), but the other numbers can be interchanged. Doesn't matter.
Plug the numbers 4 and 7 into the formula.

Now evaluate them to get 
16+49=65
To get c, take the square root of 65

The two shorter sides of the rectangle are 5cm each and the two longer ones are 8cm each. we know this because if one of the sides of the rectangle is 5cm that means the other side is also 5cm. if you add these two sides you get 10cm. if the total perimeter of the rectangle is 26cm and you know that two sides add up to 10cm then you subtract 10cm from 26cm. this will give you a remainder of 16cm for the remaining sides in question. if the total of the two remaining sides is 16cm that means that each of the remaining sides is 8cm long because 16/2 = 8