It looks like the terms are:
(7x2 + 5) and (x - 3)
Answer:
x = -0.6
y = 2.2
z = 2
Step-by-step explanation:
2x + y - 2z = -3
x + 3y - z = 4
3x + 4y - z = 5
Rewrite the system in matrix form and solve it by Gaussian Elimination (Gauss-Jordan elimination)
2 1 -2 -3
1 3 -1 4
3 4 -1 5
R1 / 2 → R1 (divide the 1 row by 2)
1 0.5 -1 -1.5
1 3 -1 4
3 4 -1 5
R2 - 1 R1 → R2 (multiply 1 row by 1 and subtract it from 2 row); R3 - 3 R1 → R3 (multiply 1 row by 3 and subtract it from 3 row)
1 0.5 -1 -1.5
0 2.5 0 5.5
0 2.5 2 9.5
R2 / 2.5 → R2 (divide the 2 row by 2.5)
1 0.5 -1 -1.5
0 1 0 2.2
0 2.5 2 9.5
R1 - 0.5 R2 → R1 (multiply 2 row by 0.5 and subtract it from 1 row); R3 - 2.5 R2 → R3 (multiply 2 row by 2.5 and subtract it from 3 row)
1 0 -1 -2.6
0 1 0 2.2
0 0 2 4
R3 / 2 → R3 (divide the 3 row by 2)
1 0 -1 -2.6
0 1 0 2.2
0 0 1 2
R1 + 1 R3 → R1 (multiply 3 row by 1 and add it to 1 row)
1 0 0 -0.6
0 1 0 2.2
0 0 1 2
x = -0.6
y = 2.2
z = 2
Complete question :
Sam knows that his MP3 player has 40% of its battery life left and that the battery
charges by an additional 12 percentage points every 15 minutes. What percent of
the mp3's battery will be charged when Sam and his family leave? If mp3 was plugged in an hour before his family plan to leave.
Answer:
88%
Step-by-step explanation:
Time before leaving = 1hour
Current percentage = 40%
Charge rate = 12% every 15 minutes
Therefore,
Charge rate per minute :
12% / 15 = 0.8% per minute
Charge recieved after one hour (60 minutes) :
0.8% * 60
= 48%
Therefore, total charge after just before leaving is:
Current percentage + percentage received
40% + 48%
= 88%
Y=2x
y is the amount of money made from the sold books
x is the number of books that are sold (it is x because you don't know how many will be sold, so you have to account for all possibilities)
2x is because every book is sold for 2 dollars, so that mean x is multiplied by 2 to get y
Answer:
10
Step-by-step explanation:
