Answer:
nth term =
Step-by-step explanation:
Let us assume that the given sequence is a G.P.
Now, if the first term of the G.P. is a and the common ratio is r, then
Third term = .......... (1) and
20th term = ........... (2)
Now, dividing equation (2) with equation (1) we get
⇒
⇒ r = 1.2.
Hence, from equation (1) we get
a(1.2)² = 11
⇒ a = 7.639 (Approx.)
Therefore, the general term of the sequence i.e. nth term = (Answer)
The mathematical mistake that Riley made is that:
"She used the wrong common denominator." (Option A)
A common denominator is a factor that is similar to all the fractions in the sequence of equations.
Hence the correct answer is:
(2(2x² - 6x + 9))/((x-3) (x-2) (x+3))
See the correct sequence of steps below:
Step One - the Expression is given as:
(x/(x-3)(x-2)) + (3/(x+3))
Step 2 - Find the common denominator and rewrite the expression so that the numerators are above the common denominators.
Hence we have: (x (x+3) + 3(x-3) (x-2))/(x-3)(x-2)(x+3)
Step 3 Apply the Law of Multiplicative Distribution:
Hence we have (x² +3x+3x²-9x-6x+16)/(x-3)(x-2)(x+3)
Step 4 - Collect Like Items
This gives us: (x²+3x²)+(3x-9x-6x)+18/(x-3)(x-2)(x+3)
Step 5 Sort for like coefficients
This gives us: ((1+3)x² +(3-9-6) * x + 18)/(x-3)(x-2)(x+3)
Step 6 - check for the sum or difference
This gives us: (4x²+(3-9-6) * x+ 18)/(x-3)(x-2)(x+3)
We simplify and factor the expression to get
(2(2x²-6x+6)/(x-3)(x-2)(x+3).
See the attached for full question.
Learn more about Common Denominators at:
