57.1k views
2 votes
40 POINTS Please someone help me with these 3 math questions got a deadline to meet

please give right answers no false

5. Evaluate the function f(x) = 4 ∙ 7^x for x = -1 and x = 2. Show your work

17. Find the roots of the quadratic equation x^2 - 8x = 9 by completing the square. Show your work

18. Use the discriminant to find the number of real solutions of the equation 3x^2 - 5x + 4 = 0 Show your work.

A water balloon is tossed into the air with an upward velocity of 25ft/s. Its height H(t) in ft after t seconds is given by the function h(t) = - 16t^2 + 25t + 3. Show your work

19. after how many seconds will the balloon hit the ground? (hint: Use the quadratic formula)

20 What will the height be at t = 1 second

1 Answer

3 votes
5. f(x) = 4 . 7^x

for x = -1

f(-1) = 4 . (7)^-1 = 4/7

for x = 2

f(2) = 4 . (7)^2 = 4 . 49 = 196

17. x^2 - 8x = 9

x^2 -8x + 16 = 9 +16
(x - 4)^2 = 25

(x - 4) = +/-5
x = 5 + 4 = 9 and x = -5 + 4 = -1

18. 3x^2 -5x + 4 = 0

Discriminant √(b^2 - 4ac) = √[(-5)^2 - 4(3)(4)] = √[25 - 48] = √(-23)

Given that √(-23) is an imaginary number, the equation does not have real solutions.
User Jaans
by
7.8k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories