Use an addition equation to solve for x. 6, 14, x

Perimeter = 35
A. 15
B. 55
C. 21
D. 29

What is the maximum total area that 450cm of string can enclose if it is used to form perimeters of two adjoining rectangles as shown?

Adam drew two same size rectangles and divided them into the same number of equal parts. he shaded 1/3 of one rectangle and 1/4 of the other rectangle. what is the least number of parts into which both rectangles could be divided into?

If f(x) = x+8 and g(x) = 4x- 3, find (f+g)(x)