If m<1=x^2+3x and m<2=8x+100, for what value of x will line m be parallel to line n?

Question

There is a graph

Answer 1

Notice that you have used the letter m in two different ways here: meaning "measure of (for angles)" and apparently as the name of a line.  If we assume that the diagram to which you refer shows lines m and n and a transversal crossing them forming angles 1 and 2 in CORRESPONDING positions, then they're parallel lines provided 

x²+3x = 8x+100.  Thus you have a quadratic equation to solve.