Answer:
Option D is the correct answer
Step-by-step explanation:
The x intercepts of the parabola are the solutions of the equation. These points can be determined either by graphical method or by solving the quadratic equation with any of the methods of solving a quadratic equation.
In order to use the graphical method, values of x are picked and substituted into the equation to get corresponding values of y. The y values are plotted against the x axis and the parabola (downward) is drawn. The points where it cuts the horizontal axis become the solutions of the equation
y = x^2 - 9x + 18
Solving the equation by using the factorization method,
x^2 - 9x + 18 = 0
x^2 - 6x - 3x + 18 = 0
x(x-6)-3(x-6)
(x-6)(x-3) = 0
x -6 = 0 or x -3 = 0
x = 6 or x = 3
The x-intercepts are (3, 0) and (6, 0)
Answer:
12 square units
Step-by-step explanation:
A = 1/2·h(sum of bases)
A = 1/2(4)(2+4)
A = 2(6) which is 12 square units
David would have to save for 7 weeks in order to have enough money for his bike.
If you would like to know how many people attended the reunion last year, you can calculate this using the following steps:
125% of last year's attendance is 160 people
125% of x is 160
125% * x = 160
125/100 * x = 160 /*100/125
x = 160 * 100 / 125
x = 128 people (last year)
Result: 128 people attended the reunion last year.
Memorize the definition of standard deviation: the sd is the square root of the average of the squared deviations of the mean. Wow. Let's do it.
Step 1. First we need the mean. That's easy. Add them up and divide by the count. Check if you get 16.88/5 = 2.81333.
Step 2. Now we're going to subtract this from each of the values, and square the result. Don't worry about negative signs, the squaring will get rid of those. Example for the first number:
(1 - 2.813)^2 = 3.29
The list of numbers I get is (rounded, in reality round as little as possible):
3.29, 2.60, 1.41, 2.35, 1.66, 6.18
Step 3: Add them all up. I get 17.49.
Step 4: Divide by the count of numbers. 17.49/6 = 2.91
Step 5: Take the square root from this result. SQRT(2.91) = 1.707305
TIP: Use excel to do all these steps, then run the set of numbers through Excel's built-in sd function (called STDEV.P) and see that you get the same result!
