SOLUTION: Hello, I am having trouble trying to figure out how to solve an equation. I just started college after being out for over 15 years so a step by step answer would be greatly apprec

Algebra ->  Parallelograms -> SOLUTION: Hello, I am having trouble trying to figure out how to solve an equation. I just started college after being out for over 15 years so a step by step answer would be greatly apprec      Log On


   

Question 665332: Hello,
I am having trouble trying to figure out how to solve an equation. I just started college after being out for over 15 years so a step by step answer would be greatly appreciated.
The perimeter of a quadrilateral is 70 inches. Find the lengths of the sides. The sides are x+2, x-5, 2x-1 and x^2-3x.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Hi.
I always say to think of the equals sign as a balance point, and whatever
you do to one side you must do to the other side, or else you will
throw the equation out of balance.
+x+%2B+2+%2B+x+-+5+%2B+2x+-+1+%2B+x%5E2+-+3x+=+70+
Group the +x+ terms and constant terms together
+x%5E2+%2B+x+%2B+x+%2B+2x+-+3x+%2B+2+-+5+-+1+=+70+
Add the +x+ terms and constant terms
+x%5E2+%2B+x+-+4+=+70+
Subtract +70+ from both sides
+x%5E2+%2B+x+-+74+
Use the quadratic equation
+x+=+%28-b+%2B-+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29+%2F+%282%2Aa%29+
+a+=+1+
+b+=+1+
+c+=+-74+
+x+=+%28+-1+%2B-+sqrt%28+1%5E2+-+4%2A1%2A%28-74%29+%29%29+%2F+%282%2A1%29+
+x+=+%28+-1+%2B-+sqrt%28+1+%2B+296+%29%29+%2F+2+
+x+=+%28+-1+%2B-+sqrt%28+297+%29%29+%2F+2+
+x+=+%28+-1+%2B+17.234+%29+%2F+2+
+x+=+16.234+%2F+2+
+x+=+8.117+
that would make the sides:
+x+%2B+2+=+10.117+
+x+-+5+=+3.117+
+2x+-+1+=+15.234+
+x%5E2+-+3x+=+65.886+-+24.351+
+x%5E2+-+3x+=+41.535+
---------------------
Adding these:
+10.117+%2B+3.117+%2B+15.234+%2B+41.535+=+70.003+
close enough