STAAR (State of Texas Assessments of Academic Readiness) Algebra I, May 2017, cont.

I had to put these on hold for a while. They're back now.

The State of Texas Assessments of Academic Readiness (STAAR) exam, administered MAY 2017.

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Administered May 2017

Read each question carefully. For a multiple-choice question, determine the best answer to the question from the four answer choices provided. For a griddable question, determine the best answer to the question.





36. What is the equation of the line that passes through the point (-2, 7) and has a slope of zero?

F x = 7
G y = -2
H x = -2
J y = 7

Answer: J y = 7
A line with a slope of 0 is a horizontal line in the form y = b. Since the point (-2, 7) is on the line, b must be 7.



37 Which ordered pair is in the solution set of y ≥ 1/3 x + 4?

A (-6, 1)
B (-1, 6)
C (6, -1)
D (1, -6)

Answer: B (-1, 6)
You don't need the provided graph, so I didn't include it in the answer. You could graph the inequality and check to see which point lies in the shaded region.
It would be quicker to just check the choices.
Is 1 ≥ 1/3 (-6) + 4?
1 ≥ -2 + 4
1 ≥ 2, X, not true, eliminate Choice A

Is 6 ≥ 1/3 (-1) + 4?
6 ≥ -1/3 + 4
6 ≥ 3 + 2/3, true. Choice B is the answer.

38. Which table does NOT show y as a function of x?

Answer: H
The only restriction on a function is that every imput has only one output.
In choice H, the value -0.2 repeats for the x value (input) but has two different y values (outputs) associated with it. This is not allowed in a function.
Consider a function to be like a function key on a calculator. You input a number and press the function key, you expect the same output every time you enter the same input. It can't be 5 sometimes and 8 other times.



39. A projectile is launched into the air from the ground. The table shows the height of the projectile, h(t), at different times.

Based on the table, which function can best be used to model this situation?

A h(t) = 99t² + 858
B h(t) = -4.9t² + 295t + 0.6
C h(t) = -4.9t² + 295t + 2
D h(t) = 99t² + 1,470.3

Answer: B h(t) = -4.9t² + 295t + 0.6
It's a projectile, so it is going to have negative acceleration. That is to say, it will be an upside-down parabola. You should also be aware that the leading coefficient is problems of these types is likely to be -16, -5, or -4.9, depending on if the question uses imperial units, and if they decide to round the numbers.
You can see that the height peaks at 30 and declines again. This means that the leading coefficient is negative. Choices A and D can be eliminated.
You can graph the other two in a graphing calculator and check the table of values, or you can do a quadratic regression in your calculator.
My graphing calculator lines out with 0.6 as the y-intercept, so +2 would be farther away.

Honestly, this is an odd problem in that B and C are so close together given the size of the values. The margin of error between them is miniscule.



40. Which value of x makes the equation 0.75(x + 20) = 2 + 0.5(x - 2) true?

F 64
G -64
H 56
J -56

Answer: J -56

0.75(x + 20) = 2 + 0.5(x - 2)
0.75x + 15 = 2 + 0.5x - 1
0.25x = -14
x = -56
I assume the "64" answers come from mathematical errors giving you either 16 or -16.

More to come. Comments and questions welcome.

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