More STAAR problems.
Administered May 2019
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. A part of an exponential function is graphed on the grid
Which inequality best represents the domain of the part shown?
A x > -2
B y > 4.5
C x > 4.5
D y > -2
Answer: A x > -2
We want the domain, which means the x values. Eliminate Choices B and D.
The x-coordinate of the starting point is -2. Its y-coordinate is 4.5. We want x.
42. What is the solution to -(6m + 8) = 4(17 - m)?
Record your answer and fill in the bubbles on your answer document.
Answer: -38
-6m - 8 = 68 - 4m
-2m = 76
m = -38
Don't forget to distribute the minus sign. Basically, watch your signs everywhere.
43. Which function is equivalent to y = 3(x + 2)2 + 7?
A y = 3x2 + 12x + 33
B y = 3x2 + 12x + 19
C y = 3x2 + 19
D y = 3x2 + 33
Answer: B y = 3x2 + 12x + 19
Option 1: Graph them all and look.
Option 2: Multiply 3(x + 2)(x + 2) and get your answer.
Option 3: which of the four choices has a vertex of (-2, 7)?
The equation in the question is in Vertex form. The choices are in standard form.
The vertex is on the Axis of Symmetry, and the formula for the Axis is x = -b/(2a).
Since neither C nor D have a b term, they can be eliminated.
Note that A and B both have 12 as the middle coefficient, so we don't need to check. Just subsitute -2 for x and see which on gives you 7.
y = 3(-2)2 + 12(-2) + 33 = 21
y = 3(-2)2 + 12(-2) + 19 = 7. The answer is Choice B.
If you wanted to multiply, then do the following:
y = 3(x + 2)(x + 2) + 7
y = 3(x2 + 4x + 4) + 7
y = 3x2 + 12x + 12 + 7
y = 3x + 12x + 19
44. Which table shows y as a function of x?
[SEE IMAGE]
Answer: H
In F, G, and J, there are repeating x values, which is not allowed in a functions. For a relation to be a function, each value in the domain (x) can be mapped to only one value in the range (y).
The y values are allowed to repeat.
45. What is the equation in slope-intercept form of the line that passes through the point (5, 0) and is parallel to the line represented by y = 1.2x + 3.8?
A y = 1.2x - 6
B y = -1.2x + 6
C y = 1.2x + 5
D y = -1.2x - 5
Answer: A y = 1.2x - 6
Parallel lines have the same slope. If the slope of the given line is 1.2, then the slope of the answer is 1.2. Eliminate choices B and D.
Next, if the line goes through the point (5, 0), then when 5 is substituted for x, y must be 0.
y = 1.2(5) - 6 = 6 - 6 = 0. Choice A is correct.
y = 1.2(5) + 5 = 6 + 5 = 11. Choice C is incorrect.
More to come. Comments and questions welcome.
More STAAR problems.
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