Split the second term 7x^2 - 8x - 12 into two terms
7x^2 + 6x - 14x - 12
Factor out common terms in the first two terms, then in the last two terms
x(7x + 6) - 2(7x + 6)
Factor out the common term; 7x + 6
<u>(7x + 6)(x - 2) </u>
8, 9 you basically just evaluate the equation in the parentheses
Answer: 4 years
Step-by-step explanation:
A(0) has to be amount at start. Assume that's 5mg
Then A(t) = 5×(0.5)^(0.25t) = 5×2^(-t/4),
(also known as 5 exp(-λ t) with λ = ln(2)/4, incidentally).
We need to such that A(t) = 2.5mg, or 2^(-t/4) is 1/2, which happens when -t/4 is -1, or t is 4.
The interest figure always means the interest for a year.
120 days is 1/3 of a year, so you'll only earn 1/3 of 6.5% .
6.5% = 0.065
1/3 of that is 0.02167 .
(0.02167) x (7,000) = 151.67
Ok, so she has 14 tickets and each ride cost 2 so that can be modeled with the following expression: x= 14-2y since she initially bought 14 tickets and 2 times the number of tickets she spends. To find the equivalent expression you could basically switch up the formula like so: 7*2-2y=x because you just need an equivalent expression, and you don't need to have such a different formula or anything like that. Hope I helped!
