Answer:
Option c
Step-by-step explanation:
The study is an observational study. An observational study is made when the researchers collect data based on what they see, hear or observe without any form of manipulation or treatment plan from the researchers. Thus, in this case, the study is an observational study because the study examines individuals in a sample, but does not try to influence the response variable/influence their responses.
Answer:
high quality = 711/895
medium quality = 112/895
low quality = 72/895
Step-by-step explanation:
72 + 112 + 711 = 895
high quality = 711/895
medium quality = 112/895
low quality = 72/895
She worked as a carpenter for 12 hours and as a blacksmith for 18 hours.
Assuming you mean she earned $20 as a carpenter and $25 as a blacksmith per hour, with a total of 30 hours for $690,
let c represent carpenter hours and b for blacksmith hours.
20c + 25b = 690
c + b = 30
Subtract b from each side so that c = 30 - b
Plug this value into the first equation
20(30 - b) + 25b = 690
600 - 20b + 25b = 690
600 + 5b = 690
5b = 90
b = 18
To find c, plug this value of b into the other equation
c + 18 = 30
c = 12
Answer:
We have the equation:
(ax^2 + 3x + 2b) - (5x^2+bx-3c)= 3x^2 - 9
First, move all to the left side.
(ax^2 + 3x + 2b) - (5x^2+bx-3c) - 3x^2 + 9 = 0
Now let's group togheter terms with the same power of x.
(a - 5 - 3)*x^2 + (3 - b)*x + (2b + 3c + 9) = 0.
This must be zero for all the values of x, then the things inside each parenthesis must be zero.
1)
a - 5 - 3 = 0
a = 3 + 5 = 8.
2)
3 - b = 0
b = 3.
3)
2b + 3c + 9 = 0
2*3 + 3c + 9 = 0
3c = -6 - 9 = -15
c = -15/3 = -5
Then we have:
a = 8, b = 3, c = -5
a + b + c = 8 + 3 - 5 = 6
