Given a1 = 1/4 and a common ratio of 8,find the 9th term in the sequence.
1 answer:
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Answer:
(a + 2b)(a - b)
Step-by-step explanation:
Assuming you require the expression to be factored
Given
a² +
ab - b² ← factor out
from each term
= (a² + ab - 2b²) ← factor the quadratic
Consider the factors of the coefficient of the b² term(- 2) which sum to give the coefficient of the ab- term (+ 1)
The factors are + 2 and - 1, since
2 × - 1 = - 2 and 2 - 1 = + 1, thus
a² + ab - 2b² = (a + 2b)(a - b) and
a² +
ab - b² =
(a + 2b)(a - b)
Here we have a system of equation like this:
from the first equation we get:
Substitute in the second equation we get:
Substitute i the first equation again we get:
We deduce that:
A is bigger than B.
from the first equation we get:
Substitute in the second equation we get:
Substitute i the first equation again we get:
We deduce that: