Find the equation of the parabola with its focus at (5,0) and it’s directrix y=2
1 answer:
Answer:
Option A
Step-by-step explanation:
From the question given in the picture attached,
Directrix of the parabola → y = 2
Focus of the parabola → (-5, 0)
Since, focus is below the directrix, parabola will open open downwards.
Equation of the parabola will be in the form of,
y - k = -4p(x - h)²
Here, (h, k) is the vertex of the parabola
p = Distance between vertex and focus or distance between vertex and directrix
Since, distance between vertex and focus = Distance between vertex and directrix
Therefore, vertex of the parabola → (-5, 1)
Now distance (p) between vertex (-5, 0) and focus (-5, 1) = 1 unit
By substituting these values in the equation,
y - 1 = -4(1)[x - (-5)]²
y - 1 = -4(x + 5)²
y = -4(x + 5)² + 1
Option A will be the answer.
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Answer:
(x, y) = (1, 3)
Step-by-step explanation:
The "work" of solving by graphing is typing the equations into a graphing calculator and highlighting the point of intersection.
___
If you're graphing these by hand, there are a couple of strategies you can use. One is to make use of the intercepts of the line. For each of these, you need to rearrange the equation to a suitable form.
<u>3y -6 = 3x</u>
To put this into "intercept form", put the variable terms on one side of the equal sign and the constant on the other. Then divide by the constant and express the resulting variable coefficients as denominators.
3x -3y = -6
x/(-6/3) +y/(-6/-3) = 1
x/(-2) + y/2 = 1 . . . . . . The x-intercept is -2; the y-intercept is 2.
Plot the intercept points and draw a line through them.
<u>y +2x = 5</u>
The intercepts for this one are found by dividing by 5:
x/(5/2) + y/5 = 1 . . . . . . The x-intercept is 2.5; the y-intercept is 5.
The other strategy you can use for this one is to rearrange the equation to slope-intercept form and make use of those numbers.
y = -2x + 5
The y-intercept is 5 (as we already found above), and the slope is -2. That means the line drops 2 units for each unit it goes to the right. Apart from the y-intercept, other points on this line will be (1, 3), (2, 1), (3, -1).
<u>Solution</u>
When you plot these lines, you find they intersect at (1, 3). That is the solution to the system of equations, the values of x and y that satisfy both equations.
so.. as you can see, we use the decimal notation for the percentages... 65% is just 65/100 and 50% is just 50/100 and so on
so.. whatever the salted amounts are, we know they'll add up to (x+175)(0.50)
thus (0.30x) + (175)(0.65) = (x+175)(0.50)
solve for "x"