That will be the points corresponding to cos 60 in 3rd quadrant
which is (-1,-2)
Question 21
Let's complete the square
y = 3x^2 + 6x + 5
y-5 = 3x^2 + 6x
y - 5 = 3(x^2 + 2x)
y - 5 = 3(x^2 + 2x + 1 - 1)
y - 5 = 3(x^2+2x+1) - 3
y - 5 = 3(x+1)^2 - 3
y = 3(x+1)^2 - 3 + 5
y = 3(x+1)^2 + 2
Answer: Choice D
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Question 22
Through trial and error you should find that choice D is the answer
Basically you plug in each of the given answer choices and see which results in a true statement.
For instance, with choice A we have
y < -4(x+1)^2 - 3
-7 < -4(0+1)^2 - 3
-7 < -7
which is false, so we eliminate choice A
Choice D is the answer because
y < -4(x+1)^2 - 3
-9 < -4(-2+1)^2 - 3
-9 < -7
which is true since -9 is to the left of -7 on the number line.
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Question 25
Answer: Choice B
Explanation:
The quantity (x-4)^2 is always positive regardless of what you pick for x. This is because we are squaring the (x-4). Squaring a negative leads to a positive. Eg: (-4)^2 = 16
Adding on a positive to (x-4)^2 makes the result even more positive. Therefore (x-4)^2 + 1 > 0 is true for any real number x.
Visually this means all solutions of y > (x-4)^2 + 1 reside in quadrants 1 and 2, which are above the x axis.
The formula is
YC x YD = AY x YB
fill in what we know:
18 x 6 = 9 x YB
108 = 9 x YB
YB = 108 / 9
YB = 12
R example: 6 1/2 = 13/2 = 6.5
For the first example, six and a half is equal to thirteen halves, which
is then equal to six point five. To do this, the rule to turn a mix
number into a fraction is by multiplying the 2 with the 6 and then add
the answer to 1, which gives 13/2 (Remember to always give the same
denominator). Finally, thirteenth halves is equal to six point five
(because when you divide 13 by 2, you get 6 and one left over. To
continue dividing, add a 0 , and so 10 goes into 2 is five. so the
decimal is 6.5
