SOLUTION: The perimeter of the triangle is 10x^2-5x+7 and the other two sides are x-7 and 3x^2+5 and I need the find the third side with a polynomial expression. I need help!!!

Algebra.Com
Question 985773: The perimeter of the triangle is 10x^2-5x+7 and the other two sides are x-7 and 3x^2+5 and I need the find the third side with a polynomial expression. I need help!!!
Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
Let A,B,C be the three side lengths

Adding the side lengths gives the perimeter of the triangle

P = A+B+C

make the proper substitutions to get

10x^2 - 5x + 7 = (x-7)+(3x^2+5) + C

now solve for C

-------------------------------------------------------


10x^2 - 5x + 7 = (x-7)+(3x^2+5) + C
10x^2 - 5x + 7 = x-7+3x^2+5 + C
10x^2 - 5x + 7 = 3x^2+x-2 + C
10x^2 - 5x + 7 - 3x^2-x+2 = C
C = 10x^2 - 5x + 7 - 3x^2-x+2
C = 7x^2 - 6x + 9


-------------------------------------------------------

The expression for the third side is 7x^2 - 6x + 9

RELATED QUESTIONS

Find the measure of the third side of a triangle if the perimeter of the triangle is... (answered by flame8855)
The measurement of two sides of a triangle are given {17x-7} and {3x^2+5}. The perimeter (answered by jsmallt9)
the measure of two sides of a triangle are given. if p is perimeter, and p=10x+5y, find... (answered by ankor@dixie-net.com)
two sides of an equilateral triangle have lenghts 3x + 1 and -2x+26. which of 21-x or... (answered by robertb)
I need help with my algebra 1. Q: the perimeter of a triangle is 136 cm. If the three (answered by richwmiller,Alan3354)
the sides of a triangle are (x+2), (3x+1) and (x+7) units. find the units of x if the... (answered by ikleyn)
two equal sides of an isosceles triangle are 3x-1 and 2x+2.the third side is 2x... (answered by Earlsdon)
The lengths of the sides of a triangle are represented by 3x, 2x+2, and 5x−7. Which (answered by mananth)
The perimeter of a triangle is 2x + 5. Find the 3rd side if the other two sides are X^2-6 (answered by Earlsdon)