Question 28 Which one represents the equation log8 25 = 2 in exponential form? Answer : 82 =25 Question 29 Determine whether the parabola y = + 18x + 2 opens up, down, left, or right. −x2 Answer: Look at the coefficient of the x squared. If it is positive then opens up. If it is negative, then opens down. This has a -1 in front of x squared so it opens down. Question 30 What is the vertex of the parabola given by y = x2 20x + 5? − First find -b 2(a) this is the x part of the vertex = - -20 2(5) = 2 now you have the x so plug that into equation for y. y = 22 20(2) + 5 – = 4- 40 +5 = -31 so the vertex is (2, -31) Question 31 If f(x) = x2 2x + 9 and g(x) = 8 x, what is (f o g)(−7)? − − Answer : First find g(-7) g(x) = 8 x – g(-7)= 8- - 7 g(-7)= 15 Now plug this into f(x) f(x) = x2 2x + 9 − f(x)= 152 - 2(15) +9 f(g(x)) = 225 -30 + 9
Question 28 Which one represents the equation log8 25 = 2 in exponential form? Answer : 82 =25 Question 29 Determine whether the parabola y = −x2 + 18x + 2 opens up, down, left, or right. Answer: Look at the coefficient of the x squared. If it is positive then opens up. If it is negative, then opens down. This has a -1 in front of x squared so it opens down. Question 30 What is the vertex of the parabola given by y = x2 − 20x + 5? First find -b 2(a) this is the x part of the vertex = - -20 2(5) = 2 now you have the x so plug that into equation for y. y = 22 – 20(2) + 5 = 4- 40 +5 = -31 so the vertex is (2, -31) Question 31 If f(x) = x2 − 2x + 9 and g(x) = 8 − x, what is (f o g)(−7)? Answer : First find g(-7) g(x) = 8 – x g(-7)= 8- - 7 g(-7)= 15 Now plug this into f(x) f(x) = x2 − 2x + 9 f(x)= 152 - 2(15) +9 f(g(x)) = 225 -30 + 9
algebra-1b-eos-study-guide-with-solutions.docx