17. ralph is 3 times as old as sarah. in 4 years ralph will only be twice as old as sara will be then. find ralph’s age now.
1 answer:
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Answer:
B, D, D, B, C
Step-by-step explanation:
1) The part of the equation that tells us the graph would open downward would be B, the negative coefficient of .
We know this because, if we reorganize the equation into the standard form y = mx + b, we get y = -(x²) + 1. This means that for any value we substitute for x, y will always be negative. The answer is B.
2) To find the zeroes of this function, we just have to see which answer makes the function, well, zero.
We have the equation y = (-16t - 2) (t - 1)
We set the equation equal to zero like this:
0 = (-16t - 2) (t - 1)
We also know that anything multiplied <em>by</em> zero will <em>equal</em> zero, so:
0 = (-16t - 2) and 0 = (t - 1)
Now we just solve for t in both equations:
0 = -16t - 2
-16t = 2
t = 2/-16 or -1/8
0 = t - 1
t = 1
So our answer will be D.
3) This time, we are given the same equation but the variable t represents time and y represents the height.
The zeroes are when y = 0, so the zeroes (which are 1 and -1/8 from the last problem) mean that the height is also at zero (which is the ground).
Furthermore, time cannot be negative, so the correct answer choice would be D.
4) We are given the same equation and story problem, but instead we are asked to find the height when the ball was thrown. In other words, we need to find the y-intercept.
The y-intercept is when t = 0, so:
y = (-16t - 2) (t - 1)
y = (-16(0) - 2) (0 - 1)
y = (-2) (-1)
y = 2
So, the correct answer is B, 2 feet.
5) This problem is a simple theoretical question. We know that the constant c will represent the vertical translation or y-intercept, so the correct answer is C.