Question

solve the triangle A= 45, a= 31, b=27

Answer 1

use cos theorem to find AB

Answer 2

31^2=(AB)^2+27^2-2(AB)*27*cos45

Answer 3

AB=x

x^2-2*27*cos45*x+27^2-31^2=0

Answer 4

http://www.wolframalpha.com/input/?i=solve+x^2-2*27*cos45*x%2B27^2-31^2%3D0

Answer 5

BTW what do you mean solve the triangle ?

Answer 6

since x is length, x cannot be negative take positive one..