Is anyone good at systems of linear equations

Asilkworm winds its cocoon out of one long silk fiber. to make silk thread, 3 to 10 of these silk fibers are unwound from their cocoons and combined into aa single thread with a typical length of 300 yards. choose a reasonable number of silk fibers in a thread write an equation to find the total length of the silk fibersused in 300 yards of the thread

Triangle xyz has vertices x(1,3), y(0,0)

Find the area of a parallelogram with base 15 yards and height 21 2/3