Two solutions of the equation Ax+By = 1 are (2, -1) and (-3,-2). Find A and B.

Substitute in the values of both given coordinates & form 2 equations:

Find the value of B from the equation 2A - B = 1:

Substitute in the B-value to the other equation:

Find the B-value using the equation from before:

Therefore the equation Ax + By = 1 would equal:

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb