Answer:

Step-by-step explanation:
<u><em>The complete options are</em></u>
a) x - 2y = 30
b) 4x - 3y = 30
c) 3x - 4y = 30
d) 6x - 6y = 30
The given equation is

<u>Verify option d</u>
we have

Divide by 6 both sides



therefore
and
are equivalent
N-8=21 should be the answer
Answer:
The percent error of Heather's calculation is <u>8%</u>.
Step-by-step explanation:
Given:
Heather measures the temperature of her coffee to be 133.4 degrees fahrenheit. It is actually 145 degrees fahrenheit.
Now, to find the percent error of Heather's calculation.
The temperature of coffee Heather measures = 133.4° F.
Coffee's actual temperature = 145° F.
So, to get the measurement in error we subtract the temperature of coffee Heather measures from coffee's actual temperature:

Now, to get the percent error:



Therefore, the percent error of Heather's calculation is 8%.
Answer:
C
Step-by-step explanation:
Given
5x + 10y - 15 ← factor out 5 from each term
= 5(x + 2y - 3) → C