While I'm waiting for new Regents exams to come along, I revisiting some of the older NY Regents exams.
More Regents problems.
Administered June 2013
Part I: Each correct answer will receive 2 credits.
16. If rx - st = r, which expression represents x?
(1) (r + st) / r
(2) r / (r + st)
(3) r / (r - st)
(4) (r - st) / r
Answer: (1) (r + st) / r
Use inverse operations isolate x:
rx = r + st
x = (r + st) / r
17. What is the solution of the equation (x + 2) / 2 = 4 / x?
(1) 1 and -8
(2) 2 and -4
(3) -1 and 8
(4) -2 and 4
Answer: (2) 2 and -4
Cross-multiply and solve the quadratic equation:
x(x + 2) = (2)(4)
x2 + 2x = 8
x2 + 2x - 8 = 0
(x + 4)(x - 2) = 0
x + 4 = 0 OR x - 2 = 0
x = -4 or x = 2
Or you could have substituted the values in the choices into the original equation and checked which ones made a true statement.
(1 + 2) / 2 ?= 4 / 1
3/2 =/= 4 (No need to check -8)
(2 + 2) / 2 ?= 4 / 2
4/2 = 4/2 (YES!)
(-4 + 2) / 2 ?= 4 / -4
-2 / 2 ?= 4 / -4
-1 = -1 (YES!)
18.Which type of function is graphed below?
(1) linear
(2) quadratic
(3) expotential
(4) absoulte value
Answer: (3) expotential
Linear is a straight line. A quadratic function would go up toward infinity on both sides, down on both sides, but not to the left. An absolute value function is V shaped.
Exponetial functions go almost horizontal on end, and ever-upward on the other.
19. What is the slope of the line represented by the equation
4x + 3y = 12?
(1) 4/3
(2) 3/4
(3) -3/4
(4) -4/3
Answer: (4) -4/3
If you didn't know that the slope of a line in Standard Form (Ax + By = C) is -A/B, then you could have found the answer by converting the equation to slope-intercept form:
3y = -4x + 12
y = (-4/3)x + 12/3
20. The diagram below shows the graph of which inequality?
(1) y > x - 1
(2) y > x - 1
(3) y < x - 1
(4) y < x - 1
Answer: (4) y < x - 1
It has a solid line which is shaded below. That makes it equal and less than.
More to come. Comments and questions welcome.
More STAAR problems.
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