Question

A point D is on the side BC of an equilateral triangle ABC such that DC = BC. Prove
that AD2 = 13 CD2 ?​

Answer 1

Answer:

Problem 1 Two of the following systems of equations have solution (1;3). Find them out by checking.

a) \displaystyle \begin{array}{|l} x + y = 5 \\ 2x - y = 7; \end{array}

x+y=5

2x−y=7