Just subtract and then add then you should get your answer.
Answer:
a = 1/2 (1 ±sqrt(47))
Step-by-step explanation:
a^2-a+12=0
We will complete the square
Subtract 12 from each side
a^2-a+12-12=0-12
a^2-a=-12
The coefficient of a = -1
-Divide by 2 and then square it
(-1/2) ^2 = 1/4
Add it to each side
a^2 -a +1/4=-12 +1/4
(a-1/2)^2 = -11 3/4
(a-1/2)^2= -47/4
Take the square root of each side
sqrt((a-1/2)^2) =sqrt(-47/4)
a-1/2 = ±i sqrt(1/4) sqrt(47)
a-1/2= ±i/2 sqrt(47)
Add 1/2 to each side
a-1/2+1/2 = 1/2± i/2 sqrt(47)
a = 1/2± i/2 sqrt(47)
a = 1/2 (1 ±sqrt(47))
Answer:
36 dollars
Step-by-step explanation:
We need to think backwards to solve this question.
(8 - 2) x 2 = 12
(12 - 2) x 2 = 20
(20 - 2) x 2 = 36
An exponential behavior can be observed.
Let x be the number of years she has to wait.
100((1+0.08/12)^12x) = 150
Now solve for x.
log base 1.08/12 of 1.5 = 61.02 approx
12x=61.02
x=5.09 years
