Five years ago:
Peter= P-5
Sam = S-5
Peter was 3 times older than Sam, which means that (P-5) = 3(S-5)
P-5 = 3S-15
So, the equation that would complete the system is C. P - 5 = 3S - 15
P-5 = 3S-15
P-3S = -15+5
P-3S = -10
So, now we use two equations: P-3S = -10 and the original one P+S=30
P-3S=-10
P+S=30 (to simplify the equation, multiply it by -1)
P-3S=-10
-P-S=-30
__________
0P-4S=-40
-4S=-40
4S=40
S=40/4
S=10
P+S=30
P+10=30
P=20
This means that Pete is 20, and Sam is 10. Hope this helps!
Answer:
Step-by-step explanation:
Add like terms.
Answer:
A solution to a system of equations means the point must work in both equations in the system. So, we test the point in both equations. It must be a solution for both to be a solution to the system. Hope this helps.
Answer:
Step-by-step explanation:
Let m denotes the number of minutes of phone use in a month.
In plan a there is no monthly fee, but the customer pays 8 cents per minute of use.
Total cost of plan a = 
In Plan B the customer pays a monthly fee of $2.40 and then an additional 7 cents per minute of use.
Total cost of plan b = 
To find amount of monthly phone use for which plan a cost more than plan b, solve the inequality 
.
Answer:
I just learned this topic and have the same question, so I'm not sure if this right. However, I see a fellow student struggling and have to at least put in what I know. My equation was f(n) = 64(1/2)^n-1, then the question was write an expression to represent f(20).
Step-by-step explanation:
So, my answer was f(20) = 64(1/2)^19
f(20) is the number you plug into n. And because the exponent is n-1, I knew to subtract 1 from 20 to get 19.
Then I just wrote the equation out like the original expect with the numbers pluged in: f(20) = 64(1/2)^19
I hope this helps!
