Answer:
Dorsey = 4.8 hours
Campbell = 24 hours
Step-by-step explanation:
It takes "x" hours for Dorsey
So, it will take 5 times more for Campbell, so
It takes "5x" hours for Campbell
Rate is inverse of time, so rates are:
Dorsey: 1/x
Campbell: 1/5x
We know Rate * Time = Work
When together, it takes 4 hours to finish a work, so we can write:

Solving for x, we get the time of Dorsey:

Dorsey takes 4.8 hours alone
Campbell takes 4.8 * 5 = 24 hours alone
Take note that they spent $18 afterwards having $28 on the card so they're spending money off the card so...
x-18=28
would be the equation for this and to solve do the following.
First add 18 to both sides making the equation.
x=46
Answer:
x = -7
, y = 0
Step-by-step explanation:
Solve the following system:
{4 x + 5 y = -28 | (equation 1)
-4 x - 7 y = 28 | (equation 2)
Add equation 1 to equation 2:
{4 x + 5 y = -28 | (equation 1)
0 x - 2 y = 0 | (equation 2)
Divide equation 2 by 2:
{4 x + 5 y = -28 | (equation 1)
0 x - y = 0 | (equation 2)
Multiply equation 2 by -1:
{4 x + 5 y = -28 | (equation 1)
0 x+y = 0 | (equation 2)
Subtract 5 × (equation 2) from equation 1:
{4 x+0 y = -28 | (equation 1)
0 x+y = 0 | (equation 2)
Divide equation 1 by 4:
{x+0 y = -7 | (equation 1)
0 x+y = 0 | (equation 2)
Collect results:
Answer: {x = -7
, y = 0
√105
if u see its factor are only 3,5,7 so it cant be simplify
answer should be √105
B
Answer:
a<-4
Step-by-step explanation:
Add 5 to both sides of the inequality
-2a>8
Then divide -2 on both sides of the inequality
And since you are dividing a negative the inequality sign has to be fliped around
a<-4
Hope this helps!!!
Have a great day!!!