Answer:
Step-by-step explanation:
We can let b and c represent the cost of a book and the cost of a CD, respectively. Then the purchases can be described by ...
3b +7c = 79
5b +2c = 35
Using Cramer's rule to find the solution, we have ...
b = (7(35)-2(79))/(7(5) -2(3)) = 87/29 = 3
c = (79(5)-35(3))/29 = 290/29 = 10
The cost of each book was $3; the cost of each CD was $10.
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Cramer's rule tells you the solution to ...
ax +by = c
dx +ey = g
is ...
x = (bg -ec)/(bd -ea)
y = (cd -ga)/(bd -ea) . . . . same denominator
This solution is fully equivalent to using elimination or substitution to solve the problem. Using these formulas effectively "cuts to the chase" without all the intermediate steps. The cross-multiplying pattern of differences is not hard to memorize.
Answer: x+y=25000
int- 0.06x +0.085 =2000
multiply by 60
multiply interest by 100
60x+60y=60*25000
60x+85y=2000000
25y=500000
divided both by 25
y=20000 (8.5%)
x=5000 (6%)
Step-by-step explanation:
To graph equations like y = -x -12
Since this is in slope intercept form we are automatically given the y-intercept which in this case is -12 so (0,-12)
the coefficient in front of the x is the slope, in this case it is -x so that means -1/1 or -1
To graph this you would plot a point at the y-intercept, then down one over one (negative slope means down instead of up) then to the right, however long to create a line
Hope this helps :)<span />