# precalculus

posted by .

Help appreciated~

1.Use the quadratic formula to determine when f(x)= x^2 +7x + 7 is greater than 0. Round your answer to two decimal places.

a) x<-5.79, x>-1.21
b) x<-7, x>1
c) 1<x<7
d) -5.79<x<-1.21
----------------------------------------
2. On what interval will the function f(x) = x^2 - 5x -6 have a positive rate of change?

a) -1<x<6
b) x>2.5
c) x<-1, x>6
d) x is less than or equal to 2.5

• precalculus -

1.
find the roots of the function: (-7 +/- sqrt(21))/2 = -5.79 and -1.21

Since the graph is a parabola which opens up, it will lie below the x-axis between the roots, and above the axis elsewhere.

2.
Again, you have a parabola which opens up. If you can find the vertex, f(x) will be decreasing on the left, and increasing on the right of the vertex.

The vertex, natch, is at x = -b/2a = 5/2.

## Similar Questions

1. ### math

round result to two decimal places...the answer i have is: 7.023 so two decimal places would it be: 702.0 You're asked to round to two decimal places. 7.023 = 7.02. Your answer has only one decimal place. so i guess my answer is wrong …
2. ### Calculus

Consider the function below. f(x) = [1-(4/x)]^x (a) Use a graph to estimate the value of the limit of f(x) as x approaches infinity. (Round the answer to two decimal places.) (b) Use a table of values of f(x) to estimate the limit. …
3. ### 5 Pre-Calculus Questions

1. What is the value of x in the right triangle below?
4. ### precalculus

Determine the x-intercepts of the polynomial function y=-6(x+7)^4 + 5. Round to two decimal places, if necessary. y=-6(x+7)^4 + 5 0=-6(x+7)^4 + 5 -5=6(x+7)^4 -5/6 =(x+7)^4 There are no x-intercepts?
5. ### Chemistry

1. Calculate the pH of a buffer solution that contains 0.32 M benzoic acid (C6H5CO2H) and 0.17 M sodium benzoate (C6H5COONa). [Ka = 6.5 × 10-5 for benzoic acid] Round your answer to two places past the decimal. 2. A solution is prepared …
6. ### Chemistry

1. Calculate the pH of a buffer solution that contains 0.32 M benzoic acid (C6H5CO2H) and 0.17 M sodium benzoate (C6H5COONa). [Ka = 6.5 × 10-5 for benzoic acid] Round your answer to two places past the decimal. 2. A solution is prepared …
7. ### college stats

Again sorry for all the questions. please help, I am not good at stats and find these questions very difficult. I would appreciate an explanation if possible. 1.What is the sample average?
8. ### Pre Calc

Use the doubling time to find the continuous percent growth rate and give a formula for the function. Round your answer to two decimal places. I found the doubling time to be 24 days and the continuous percent growth rate to be 2.89% …
9. ### Probability and statistic

Suppose X has an exponential distribution with mean equal to 13. Determine the following: (a) Upper P left-parenthesis x ⁢ greater-than 10 right-parenthesis (Round your answer to 3 decimal places.) (b) Upper P left-parenthesis …
10. ### math

(a) Make a table of values rounded to two decimal places for the function f(x) = ex for x = 4, 4.5, 5, 5.5, and 6. Then use the table to answer parts (b) and (c). (b) Find the average rate of change of f(x) between x = 4 and x = 6. …

More Similar Questions