The expression (3x−1)(x+5) is equivalent to?
3x2+14x+5
3x2+14x−5
4x2+16x+6
4x2−16x−6

(3x−1)(x+5)

Mutiply

(3x)(x)(3x)(5)(-1)(x)(-1)(5)

3x^2+15x-x-5

3x^2+14x-5

Answer : 3x^2+14x-5

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