Plug in 6.5 for x.
-8.5x-3.5x=-78
-8.5(6.5)-3.5(6.5)=-78
-55.25-22.75=-78
-78=-78
Answer:
4
Step-by-step explanation:
1. if the mass of coffee worth $10 is 'x', then its worth is 10x, and the worth of the mixture is 5(x+20);
2. using the previous item it is possible to write the next equation:
5(x+20)=4*20+10*x; ⇒ x=4.
3. the required mass is 4 pounds.
Answer:
Part A: The price of 1 pound of potatoes is 1 dollar and 25 cents (1.25) because 5 / 4 is 1.25 and that's 1 pound
Part B: The ordered pair (10, 8) represents that 10 punds of potatoes cost 8 dollars
Answer: 
Step-by-step explanation:
x^2+y^2=r^2 --> subtract x^2 to other side
y^2=r^2-x^2 --> square root both sides
y=sqrt(r^2-x^2)
The better buy should be buy twelve cans for 7 dollors
Given that,
- twelve cans for7 dollors or 6 cans for 4 dollors.
Based on the above information, the calculation is as follows:
The first option is

= $0.58
The second option

= $0.67
Learn more: brainly.com/question/16911495