The sum formula for a geometric sequaence is:
sum(n) = a1(1-r^n)/1-r
Where n is the number of terms, a1 is the first term and r is the common ratio:
s(8) = 3(1-1/2^8) / (1-1/2)
s(8) = 3(1-1/256) / 1/2
s(8) = 2 253/256 / 1/2
s(8) = 765/128
The answer is C.
Slope intercept form is y=mx+b
m=slope
b=y-intercept
the slope is the rate of change of the graph, basically rise/run (change in y divided by change in x)
the y intercept is where the graph intercepts the y axis
we usually use this form because we can find the slope and find where it hits the y axis.
there are other forms that may be helpful later on, but this one is usually the easiest form to find from a graph
A real word problem could be that max has 3/4 of a chocolate bar and he wants to divide the chocolate with 1/6 of her class. If he does that, how much will each person get?
We need a picture of the shape.
Answer:
24 years old
Step-by-step explanation:
Let the age of Blake be x and the age of Heather by y then...
x=7+y
7+x+7+y=55
Notice we are adding additional 7s because the question states "in 7 years"
Simplify the second equation...
7+x+7+y=55
14+x+y=55
Subtract 21 from both sides
x+y=41
Solve using substitution (substitute 7+y for x since x = 7+y)
7+y+y=41
Combine like terms
2y+7=41
Subtract 7 from both sides
2y=34
Divide both sides by 2
y=17
x=7+17=24
Blake is 24 years old now
