The solution is (5, 15)
Multiply the second equation by 2 and then add through.
3x + 2y = 45
8x - 2y = 10
-----------------
11x = 55
x = 5
Then plug in to get the y value
3(5) + 2y = 45
15 + 2y = 45
2y = 30
y = 15
Answer:
x = 7
y = 11
Step-by-step explanation:
Given the system;
y = 2x - 3
x + y = 18
1. Approach
The easiest way to solve this system of equations is to solve the second equation for the variable (y). Then add the systems, use algebra to solve for the value of (x), then substitute that value back into one of the original equations to solve for the value of (y). Another name for the method in use is the method of elimination, this is when a [erspm manipulates one of the equations in a system of the equation such that when they add the equations, one of the variables eliminatates. Thus, they can solve for the other variable and the backsolve for the value of the unknown variable.
2. Solve one of the equations for a variable
Manipulate the system such that each equation is solved for the same variable,
x + y = 18
Inverse operations,
x + y = 18
-18 -18
x + y - 18 = 0
-y -y
x - 18 = -y
3. Use elimination
Now substitute this back into the original system,
y = 2x - 3
-y = x - 18
Add the systems,
y = 2x - 3
-y = x - 18
_________
0 = 3x - 21
Inverse operations,
0 = 3x - 21
+21 +21
21 = 3x
/3 /3
7 = x
4. Find the value of the unknown variable
Backsovle to find the value of (y),
x + y = 18
Substitute,
7 + y = 18
Inverse operations,
7 + y = 18
-7 -7
y = 11
Answer:
(a) 95% confidence interval for the percent of all adults who want to lose weight is (48%, 54%) that is between 48% and 54%
(b) to say that we have 95% confidence in this interval means that there is 95% chance that the true percentage of all adults who wants to lose weight falls in this interval.
Step-by-step explanation:
The question is missing, complete question is below:
A Gallup Poll found that 51% of the people in its sample said "yes" when asked, "Would you like to lose weight?" Gallup announced: "With 95% confidence for results based on the total sample of national adults, one can say that the margin of sampling error is ± 3%."
(a) What is the 95% confidence interval for the percent of all adults who want to lose weight?
(b) What does it mean to say that we have 95% confidence in this interval?
Confidence Interval can be calculated using p±ME where
- p is the sample proportion of national adults who want to lose weight (51%)
- ME is the margin of sampling error (± 3%)
