Answer:-
x=-5/2
Step-by-step explanation:
x+2/3=-1/6
after cross-mutiplying,
6(x+2)=-3
6x+12=-3
6x=-3-12
6x=-15
x=-15/6
x=-5/2
hope this helps u!!
We're going to go ahead and eliminate one answer out of the four. It <u>cannot be B</u> (the second answer) <em>because the graph is made of dotted lines. </em>
Dotted Lines = > or <
Solid Lines = ≤ or ≥
Next, let's focus on the straight line on the graph.
The equation for the line is
y = x - 4
Since the shaded region is <em>below </em>the line,
the equation will be <u>y < x - 4 </u>
We can now <u>eliminate </u>answer <u>A </u>
Since the second equation is y < - l x - 2 l
It will be shaded below the graph since it uses the ( < ) (less than symbol)
This means <em><u>the answer is C</u></em>
Hope I helped, message me if you have any questions : )
OK, so the graph is a parabola, with points x=0,y=0; x=6,y=-9; and x=12,y=0
Because the roots of the equation are 0 and 12, we know the formula is therefore of the form
y = ax(x - 12), for some a
So put in x = 6
-9 = 6a(-6)
9 = 36a
a = 1/4
So the parabola has a curve y = x(x-12) / 4, which can also be written y = 0.25x² - 3x
The gradient of this is dy/dx = 0.5x - 3
The key property of a parabolic dish is that it focuses radio waves travelling parallel to the y axis to a single point. So we should arrive at the same focal point no matter what point we chose to look at. So we can pick any point we like - e.g. the point x = 4, y = -8
Gradient of the parabolic mirror at x = 4 is -1
So the gradient of the normal to the mirror at x = 4 is therefore 1.
Radio waves initially travelling vertically downwards are reflected about the normal - which has a gradient of 1, so they're reflected so that they are travelling horizontally. So they arrive parallel to the y axis, and leave parallel to the x axis.
So the focal point is at y = -8, i.e. 1 metre above the back of the dish.
