A rectangle with sides 7 and #x+2# has a perimeter of 40 units. What is the value of #x#?

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Answer 1 · 2018-04-25T19:51:46

#=>x = 11#

For a length #l# and width #w#, the perimeter of the rectangle is given as:

#P = l + l + w+ w = 2l + 2w = 2(l+w)#

We are given two sides. It doesn't matter which is which, so let's use #l = 7# and #w=x+2#.

Using our perimeter equation:

#40 = 2(7+(x+2))#

Now we solve for #x#.

#40 = 2(x+9)#

#40 = 2x+18#

#22 = 2x#

#11 = x#