Explanation:
First, add by 25 both sides of an equation.

Then, simplify by equation and add/subtract by the numbers.

*The answer must be have a negative sign.

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Answer:
A+6+A = 20
A = 7
Step-by-step explanation:
J = number of problems Juana completed
A = number of problems Andy completed
J+A=20
J = A + 6
Replace J with A+6 in the first equation
A+6+A = 20
2A +6 = 20
Subtract 6 from each side
2A +6-6 = 20-6
2A =14
Divide by 2
2A/2 = 14/2
A = 7
Answer:
-6
Step-by-step explanation:
3n = n² - 54
n² - 3n - 54 = 0
n² - 9n + 6n - 54 = 0
n(n - 9) + 6(n - 9) = 0
(n - 9)(n + 6) = 0
n = 9 , -6
ANSWER
The vertex is (1,-3)
EXPLANATION
The given parabola has equation:

We group the variables to obtain:

We complete the square to get,



The vertex is of the parabola is (1,-3)
Answer:
$4
Step-by-step explanation:
The two purchases can be written in terms of the cost of an adult ticket (a) and the cost of a student ticket (s):
7a +16s = 120 . . . . . . . . price for the first purchase
13a +9s = 140 . . . . . . . . price for the second purchase
Using Cramer's rule, the value of s can be found as ...
s = (120·13 -140·7)/(16·13 -9·7) = 580/145 = 4
The cost of a student ticket is $4.
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<em>Comment on Cramer's Rule</em>
Cramer's rule is particularly useful for systems that don't have "nice" numbers that would make substitution or elimination easy methods to use. If you locate the numbers in the equation, you can see the X-patterns that are used to compute the numerator and denominator differences.
The value of a is (16·140 -9·120)/(same denominator) = 1160/145 = 8. I wanted to show you these numbers so you could see the numerator X-pattern for the first variable.
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Of course, graphical methods can be quick and easy, too.