Answer:
a) x= 5 or x= -3
b) x = -4 + 
or -4 -
Step-by-step explanation:
a) 
- 2x - 15 =0
x = 
or 
x= 5 or x=-3
b) + 8x - 10 =0
x = 
or 
x = -4 + or -4 -
Answer:
Paolo made an error when he cross multiplied the proportion
Step-by-step explanation:
The proportion is ...
"Cross multiply" means "multiply both sides of the equation by the product of the denominators."
It represents the ounces of water that the bottle can still hold.
Answer:
26 minutes on the bicycle
Step-by-step explanation:
Let t and b represent the number of minutes on the treadmill and bicycle, respectively. The problem statement tells us two ways to relate these values.
t + b = 60 . . . . . Amy exercises a total of 60 minutes (1 hour)
9t +6.5b = 475 . . . . . she burns a total of 475 calories
Since we want to find the value of "b", we can use the first equation to write an expression that will substitute for t.
t = 60 -b
9(60 -b) +6.5b = 475
540 -2.5b = 475 . . . . . . simpify
-2.5b = -65 . . . . . . . . . . subtract 540
b = 26 . . . . . . . . . . . . . . . divide by -2.5 (equivalently, multiply by -2/5)
Amy spends 26 minutes exercising on the bicycle.
