The figure below shows a rectangle ABCD having diagonals AC and DB.

 b) ΔADC ≡ ΔBCD by SAS

Step-by-step explanation:

Step 1: AD = BC                     SIDES are congruent

Step 2: ∠ADC ≡ ∠BCD          ANGLES are congruent

Step 3: DC = DC                    SIDES are congruent

The proof is using Side-Angle-Side (SAS)

Look at the angles in step 2.  These are the triangles you are proving congruency for: ΔADC ≡ ΔBCD

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

i dont understand the question? ?

step-by-step explanation: