+0  
 
+1
83
2
avatar+9 

2. What is a solution of x² + 6x = –5? 

x = –6

x = –1

x = 1

x = 6

 

 

 

3. Which of the following is a solution of x² + 14x + 112 = 0? If necessary, round to the nearest hundredth. 

x = –0.24

x = –4.24

4.24

no solution 

ribbondollop45  Mar 21, 2017
Sort: 

2+0 Answers

 #1
avatar
0

Solve for x 
x^2 + 6 x = -5

Add 9 to both sides:
x^2 + 6 x + 9 = 4

Write the left hand side as a square:
(x + 3)^2 = 4

Take the square root of both sides:
x + 3 = 2 or x + 3 = -2

Subtract 3 from both sides:
x = -1 or x + 3 = -2

Subtract 3 from both sides:
Answer: | x = -1        or          x = -5


Solve for x:
x^2 + 14 x + 112 = 0

Subtract 112 from both sides:
x^2 + 14 x = -112

Add 49 to both sides:
x^2 + 14 x + 49 = -63

Write the left hand side as a square:
(x + 7)^2 = -63

Take the square root of both sides:
x + 7 = 3 i sqrt(7) or x + 7 = -3 i sqrt(7)

Subtract 7 from both sides:
x = 3 i sqrt(7) - 7 or x + 7 = -3 i sqrt(7)

Subtract 7 from both sides:
Answer: | x = 3 i sqrt(7) - 7         or            x = -3 i sqrt(7) - 7

P.S. Neither solution agrees with your multiple choices!!.

Guest Mar 21, 2017
 #2
avatar+75344 
+2

2. x^2 + 6x   = -5    add 5 to both sides

 

   x^2 + 6x + 5   = 0        factor

 

(x + 5) ( x + 1)   = 0       set each factor to 0

 

x + 5  = 0                   x + 1   = 0

 

x = -5                          x = -1               and these are the solutions

 

 

 

3.  x^2 + 14x + 112  = 0      

 

Using the discriminant  we have

 

14^2  - 4(1)(112)  =

 

196 - 448  =

 

-252   ....so    this has no real solution

 

 

 

cool cool cool

CPhill  Mar 21, 2017

25 Online Users

avatar
avatar
avatar
avatar
We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details