Answer:
(-1/2, 3/4)
Step-by-step explanation:
Let's use the elimination by adding or subtracting method. Note that we have 8y in the first equation, and that we could obtain -8y in the second equation by multiplying the second equation by 2:
2(24x - 4y = -15) => 48x - 8y = -30
Now combine this result (this equation) with the first equation:
2x + 8y = 5
+48x -8y = -30
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50x = - 25
Dividing both sides by 50, to isolate x, we get
x = -25/50 = -1/2.
Now substitute -1/2 for x in the first equation and solve the resulting equation for y:
2x + 8y = 5
2(-1/2) + 8y = 5, or -1 + 8y = 5, or 8y = 6 (after having added 1 to both sides)
Dividing both sides of 8y = 6 by 8 leads to determining the value of y:
y = 6/8 = 3/4
The solution is (-1/2, 3/4).
Hey so yeah this can be a challenging problem, Vol (V) is much easier to solve than surface area (SA), but I'll show you how it's done, my friend.
First of all, V (prism) = area of base (B) × h
We know that the height (h) of this prism is given, which we'll need later on: h = 5 ft, and area of base (B) is given as 60 ft2
So V = 60 ft2 × 5 ft = 300 ft3
So now for the hard part... how to calculate the SA of this prism
IF YOU DON'T NEED SA FOR THIS TYPE OF PROBLEM, DO NOT PROCEED!!!
[VERY DETAILED]
means solving the dimensions (sides) of that pesky polygon base (B) or lid.
The most important things about polygons are:
1) is it regular (same angle ° and side length)??
2) How many sides or angles??
This has to be regular, because they give you no other info so it has to be, in order to solve. And then it has 5 sides and angles = regular pentagon. ("penta" means 5).
Now there are 360° in any circle, so:
take the central angles of where the sides meet at the center forming triangles (see drawing above), each of those (5) central <'s = 360/5 = 72°
Now the apex of each of these triangles = 72°
but with our 5 triangles, we need to find the height of each triangle -- which is the midpoint of the side (base (b) of triangle), and h is perpendicular to this b. By bisecting that apex angle of 72, it forms 2 equal right triangles of
72/2 = 36°. So each right triangle has 36, 90, and?? 180-36-90 = 90-36 = 54°
let's call the base (b) = 1 side of pentagon
= side (s)
Therefore (see 2nd image drawn above) tangent (tan) of € = opposite/adjacent, or
tan (54) = h÷1/2b --> h = [tan (54)]×(1/2)b
1/2b = h/[tan (54)] = h/1.38
Also the area of each of the larger 5 triangles A(t) = 1/2b×h, and that area A(t) × 5 = area of whole pentagon base A(B)
So now after all that... our A(B) given at beginning = 60ft2. let's put it all together:
1/2b = h/[tan (54)] = h/1.38
A(t) = 1/2b×h, and A(B) = 5×A(t)
which means that A(B) = 5×(1/2b×h)
AND since the other calculation shows that 1/2b = h/1.38, plug that value into the A(B) formula...
.
.
.
now that we have height (h) of each triangle, we can go back to our tan equation for the triangle: tan (54) = 1.38 = h/(1/2b)
--> 1/2×b = h/1.38 --> base (b) = 2h/1.38
b = 2(4.06 ft)/1.38 = 8.12 ft/1.38 = 5.90 ft, for which b us also the width of each rectangular side panel (w)
length (l) of these sides was given as height of the whole prism = 5 ft
NOW FINALLY... THE FINAL SURFACE AREA OF THE PRISM (SA) = (2×A(B)) + (5×rectangular side)
SA = (2×60 ft2) + (5×(l×w)) = 120 ft2 + 5×5ft×5.9ft
SA = 120 ft2 + 147.62 ft2 = 267.62 ft2
Answer:
Choice D is correct
Step-by-step explanation:
The first step is to write the polar equation of the conic section in standard form by dividing both the numerator and the denominator by 2;
The eccentricity of this conic section is thus 1, the coefficient of cos θ. Thus, this conic section is a parabola since its eccentricity is 1.
The value of the directrix is determined as;
d = k/e = 3/1 = 3
The denominator of the polar equation of this conic section contains (-cos θ) which implies that this parabola opens towards the right and thus the equation of its directrix is;
x = -3
Thus, the polar equation represents a parabola that opens towards the right with a directrix located at x = -3. Choice D fits this criteria
Represent as
w=wally
a=ashan
so wally has 2 more marbles than ashan
w=2+a
together they have 88
w+a=88
since w=2+a, subsitute (2+a) for w in the w+a=88 equation
2+a+a=88
add like terms
2+2a=88
subtract 2 from both sides
2a=86
divide by 2
a=43
ashan has 43 marbles
