Find the values of x and y

Hi there!

The two trapezoids are similar, so we can determine a common scale factor:

OL/UR = NM/TS

9/3 = 6/2

3 = 3

Trapezoid ONML is 3x larger than UTSR, so:

RS = 4, LM = y

3RS = LM

3 · 4 = y = 12.

Find x using the same method:

3UT = ON

3(2x+1) = 4x + 9

6x + 3 = 4x + 9

2x = 6

x = 3.

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

answer:

c. the third graph