Freshman math question.?

Question

I only really need help with C and D, but A and B might help with answering it.

okay, so i'm totally stumped on this one question, and i only need to finish this one to be done, so please help me! These are the questions, but I really only need help with c and d:

A. why does an equation of the form y= mx+b make a straight a straight? why does an equation in the form of ax + by = c also make a straight line?

B. The points (3,4)(11,6) and (23,9) all lie on a line. Explain how you can be sure about this without actually drawing the line.

C. Calculate the coordinates of another point on this same line whose x coordinate is greater than 800.

D. How long of a shadow would a light 30 fight off the ground make when shining on an object 10 feet tall that is 20 feet away from the light?

thanks!

Answer 1

A.value of y and x  vary linearly.for a fixed value of m(slope) and b(y intercept).in other words these equations r called linear equations.

B)in the above three coordinetes ..two points always lie on a line...(u can draw straight line through two points)so find equation of line using any two coordinetes and if third point satisfies the resultion equation then u can tell that all lie on a single line..

c)use the same line equation which u derived from two points n put value of x grater than 800

d)answer is 10 feet...its trignometry question..try to darw the diagram..use ur mind little bit u will be able to solve the diagram....if u cant solve it n .if u want that diagram ..mail me...i will reply back