9514 1404 393
Answer:
y was not substituted for every x
Step-by-step explanation:
To find the inverse of ...
y = f(x)
you need to solve ...
x = f(y)
Here, f(x) = x^2 +12x, so f(y) = y^2 +12y
This is not the expression we see on the right of ...
x = y^2 +12x
Apparently y was not properly substituted into f(x).
<span>let x = the original no. of students
then
(x+10) = the actual no. that went on the trip
:
= the original cost per student
and
= the actual cost
:
Original cost - actual cost = $12.50
- = 12.50
multiply equation by x(x+10)
x(x+10)* - x(x+10)* = 12.50x(x+10)
Cancel the denominators
1500(x+10) - 1500x = 12.5x(x+10)
1500x + 15000 - 1500x = 12.5x^2 + 125x
Combine on the right to form a quadratic equation
0 = 12.5x^2 + 125x - 15000
Simplify, divide equation by 12.5
x^2 + 10x - 1200 = 0
You can use the quadratic formula; a=1; b=10; c=-1200, but this will factor to
(x + 40(x - 30) = 0
The positive solution is what we want here
x = 30 students in the original group
Check this by finding the cost per student for each scenario
1500/30 = $50.00; original cost
1500/40 = $37.50; actual cost
---------------------
saving: $12.50</span>
Answer:
Obtuse Angles are
1, 3, 5, 7, 9, 11
Acute angles are
2, 4, 6, 8, 10, 12
Step-by-step explanation:
Answer:
Step-by-step explanation:
This is a quadratic expression. Use the quadratic formula to find the roots, and then once you have the roots, write the corresponding factors.
The coefficients of this quadratic expression are a = 7, b = 5 and c = -3
The discriminant is b^2 - 4ac, or 5^ - 4(7)(-3), or 25 + 84 = 109. Because this is positive, we know that the expression has two unequal, real roots.
Using the quadratic formula, we now find these roots:
-b ± √(discriminant)
x = -------------------------------- which here is:
2a
-5 ± √109
x = -----------------
14
The factors can be found from these two roots. The first one is
-5 - √109 5 + √109
(x - ---------------- ) = (x + ---------------- )
14 14
and the second is
5 - √109
(x + ---------------- )
14
