mcdougal littel ablebra2 less.1.3 prac. b- i dont understand a portion of this worksheet.?

Question

i ahve summer math homework, which includes review. in lesson 1.3 practice b, numbers 22 and 23 confuse me. it asks me to find the demensions of the trangle. it gives me the perimeter (35), the gives me the 3 sides: 3x-5, 2x-3, and 15-x. i have an answer key that tells me the demensions, but i don't understand how to calculate them!! please help.

Answer 1

Well, if the perimeter (thats all the way around the outside or all three sides together is 35, then you can add up the three sides and they should equal 35

3x-5 + 2x-3 + 15-x = 35

a little algerbracadabra : 3x+2x-x-5-3+15=35

then 4x=28
and x=7

so , put 7 back in for x for each of the sides and you get
3(7)-5=16
2(7)-3=11
15-(7)=8

double check just to be sure 16+11+8=35

hurrah
keep at it
math is power

Answer 2

Basic algebra solution:

(3x-5) + (2x-3) + (15-x) = 35
(5x-8) + (15 -x) = 35
4x + 7 = 35
4x = 28
x = 7

Answer 3

the other answers look pretty good. what confused me, and may be confusing you, is that it asked for 'dimensions'. it may be looking for side lengths? dimensions sounds like it wants the size of a rectangle it would fit into, but that is so confusing.