Find the measure of the sides of an equilateral PQR if PQ = 5x - 7 and PR = 2x +5.

Question

I cannot understand this!

Answer 1

An equilateral triangle PQR has all sides of equal lengths.

If PQ = 5x - 7, and
PR = 2x +5, then we can conclude that
PQ=PR, or
5x-7=2x+5
Solve for x
5x-2x = 5+7
3x = 12
x = 4
Substitute x=4 into 5x-7 to get

So each side of the triangle is 5*4-7=13 units in length.