+0  
 
0
12980
5
avatar

Express the values of x that satisfy the inequality -3 ≤ x < 7 as an interval.

 

Find all values of s (s + 4)(s - 3) ≤ 0such that . Give your answer as an interval.

 

Find all values of x that satisfy x(x+7.5) > 38.5. Give your answer in interval notation.

 

Find all values of t such that 8t^2 ≤ 3-10t.

 

Find all values of z such that {3-z}/{z+1} ≥ 1. Answer in interval notation.

 

For how many integers b does the inequality z^2 + bz + 15 < 0 have no real solutions z?

 

Find all values of c such that c^3 + 4c > 5c^2. Answer with interval notation.

 Jul 8, 2016
 #1
avatar+129839 
+1

Express the values of x that satisfy the inequality -3 ≤ x < 7 as an interval.

 

[-3, 7)

 

 

 

Find all values of s (s + 4)(s - 3) ≤ 0   Give your answer as an interval.

 

Let's solve this

 

s(s + 4)(s -3)  = 0      the three solutions are s =0, s = -4 and s = 3

 

Then, the solutions to this inequality  will occur on one or more of these possible intervals (-infinity, -4] , [-4, 0], [0,3] or [3, ifinity)

 

The intervals  (-infinity, -4]   and [0, 3]  will satify the inequality.....here's a graph : 

 

 

 

cool cool cool

 Jul 8, 2016
 #2
avatar+129839 
-1

Find all values of x that satisfy x(x+7.5) > 38.5. Give your answer in interval notation.

 

Let's solve this :  x(x + 7.5) = 38.5     subtract 88.5 from both sides and simplify

 

x^2 + 7.5x - 38.5 = 0     factor as

 

(x -  3.5) ( x + 11)  = 0        the solutions will come from one or more of these intervals :

 (-infinity, -11) , (-11, 3.5)  or (3.5, infinity)

 

The interval containing x = 0  will not satisfy the inequality which means that the intervals (-infinity, -11) and (3.5 , infinity) will make the inequality true

 

Here's the graph : https://www.desmos.com/calculator/ojmbgewyuz

 

 

 

cool cool cool

 Jul 8, 2016
 #3
avatar+129839 
-1

For how many integers b does the inequality z^2 + bz + 15 < 0 have no real solutions z?

 

This will have no integer solutions when :

 

 l b^2 l  - 4(1)(15)  < 0    simplify

 

 l b^2 l  - 60 < 0

 

 l b^2 l < 60

 

And this will be true for  all integer values  on the interval   [-7, 7].........so......the inequality will have no solutions when b is an integer  from -7 to 7, inclusive

 

 

 

cool cool cool

CPhill  Jul 8, 2016
 #4
avatar
0

Find all values of c such that c^3 + 4c > 5c^2. Answer with interval notation.

 

c3-5c2+4c>0

c(c-1)(c-4)>0

possible intervals are:\((-\infty, 0), (0, 1), (1, 4), (4, \infty)\)

Test: -1

-1(-2)(-5)<0

 

Test: ½

(.5-1)(.5-4)/2=-.5(-3.5)/2=(7/2)/2=7/4>0

 

Test: 2

2(1)(-2)<0

 

Test: 5

5(4)(1)>0

 

intervals are: \((0, 1), (4, \infty)\)

 Aug 9, 2016
 #5
avatar
0

-3x<7.5?

 Feb 15, 2017

7 Online Users

avatar
avatar
avatar