Answer:
It would be option two: Bill's Electric Company charges 6 dollars per hour plus a flat rate of 15 dollars for a service call. If Monica has at least 100 dollars to spend, how many hours can the service man work?
Step-by-step explanation:
6 dollars an hour means it would be 6x.
A flat rate of 15 means there would be just 15 as a number, no x's.
And the sign is less than or equal to, so she has over a hundred dollars to spend.
Answer:
11
Step-by-step explanation:
The two equations appear to be ...
- 12x +4y = 152
- 32x +12y = 420
These can be solved for y using Cramer's rule:
y = (152(32) -420(12))/(4(32) -12(12)) = -176/-16 = 11
The cost of the vegetarian lunch is 11.
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<em>Comment on Cramer's Rule</em>
For equations ...
ax +by =c
dx +ey = f
The solutions are ...
x = (bf -ey)/(bd -ea)
y = (cd -fa)/(bd -ea) . . . . note the denominators are the same expression
Once you memorize the pattern of products, this can be the simplest way to solve a pair of equations--especially if you only need one of the variable values.
The answer is: x = 2 ∨ x = -1
