## Saturday, March 06, 2021

### 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 2018.

More STAAR problems.

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.

41. Which expression is a factor of 18x2 - 15x + 2?

A 3x - 2
B 9x - 1
C x - 2
D 2x - 1

Answer: A 3x - 2
We can factor the trinomial, using "borrow & payback". Multiply (18)(2) = 36. What are two factors of +36 that add up to -15? They both have to be negative numbers.
Check them all: -1 and -36, no; -2 and -18, no; -3 and -12, bingo! (You can stop now)

18x2 - 15x + 2
18x2 - 12x - 3x + 2
Group the terms
(18x2 - 12x) - (3x - 2)
Now find the GCF of each pair
6x(3x - 2) - 1(3x - 2)
(6x - 1)(3x - 2) are the factors

The answer is A.

42 The graph of linear function g is shown on the grid.

What is the zero of g?
Record your answer and fill in the bubbles on your answer document.

Answer: -6
The zero is where the line crosses the x-axis, which is -6.

43. Which quadratic function in vertex form can be represented by the graph that has a vertex at (3, -7) and passes through the point (1, -10)?

A y = 3/4 (x + 3)2 + 7
B y = -3/4 (x + 3)2 - 7
C y = 3/4 (x - 3)2 + 7
D y = -3/4 (x - 3)2 - 7

Answer: D y = -3/4 (x - 3)2 - 7
The point (1, -10) is unnecessary information and no calculation is needed.
You are given the vertex and the four choices are in vertex form.
Choice D is the only possible answer as A, B, and C do not have vertices at (3, -7).

The one thing that (1, -10) tells you is that the parabola must open downward because -10 is below -7, so the number in the front must be negative.

44. The graph of part of linear function g is shown on the grid.

Which inequality best represents the domain of the part shown?

F -9 < x ≤ 2
G -9 ≤ x < 2
H -6 < g(x) ≤ 3
J -6 ≤ g(x) < 3

Answer: F -9 < x ≤ 2
The domain is the possible x values, and the range is the possible g(x) values. Eliminate Choices H and J.
There is an open circle at x = -9 that indicates it is not part of the solution, and a closed circle at x = 2 that indicates it is part of the solution. This means Choice F.

45. A student graphed f(x) = x and g(x) = f(x) + 3 on the same coordinate grid. Which statement describes how the graphs of f and g are related?

A The graph of f is shifted 3 units up to create the graph of g.
B The graph of f is steeper than the graph of g.
C The graph of f is shifted 3 units down to create the graph of g.
D The graph of f is less steep than the graph of g.

Answer: A The graph of f is shifted 3 units up to create the graph of g.
Whatever answer you would get for f(x), g(x) will always be 3 more than that. Since f(x) and g9x) are measured on the y-axis, adding through will move the points upward.
Adding or subtracting to a function will not affect its steepness. You would need to multiply.

More to come. Comments and questions welcome.

More STAAR problems.

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