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SHOW WORK PLZ!! SO I CAN LEARN IT BETTER

 Sep 26, 2018
edited by Guest  Sep 26, 2018
 #1
avatar+128474 
+2

1)

4x^2 + 16x  = 48      subtract 48 from both sides

 

4x^2 + 16x  - 48  = 0      factor out the 4

 

4(x^2 + 4x - 12)  = 0      divide away the 4

 

x^2 + 4x - 12   = 0        factor this

 

(x + 6) ( x - 2)   = 0

 

Set both factors to 0  and solve for x and we get that   x  = -6   or  x = 2

 

2)

x^2 + 7x  = -6    add 6 to both sides

 

x^2 + 7x + 6  = 0    factor the left side 

 

(x + 6) ( x + 1)   = 0     

 

Set both factors to 0  and solve for x and we get that   x  = -6   or  x = -1

 

 

cool cool cool

 Sep 26, 2018
 #2
avatar+128474 
+2

1)

 

x^2 - 3x  = 18     subtract  18 from both sides

 

x^2  - 3x - 18  = 0    factor the left side

 

(x - 6) ( x + 3)   = 0

 

Set both factors to 0  and solve for x and we get that   x  = 6   or  x = -3

 

 

2) 

 

x^2   - 3x +  ___   =  18  +   ___

 

Take 1/2 of 3  = 3/2...square this  = 9/4...add to both sides

 

x^2  - 3x + 9/4  =  18 + 9/4        factor the left side  and simplify the right

 

(x - 3/2)^2  = 72/4 + 9/4

 

(x - 3/2)^2  =  81/4         take both roots 

 

x - 3/2  = ±√ [ 81/4]    take the square root on the right

 

x - 3/2 = ± 9/2     add 3/2 to both sides

 

x = 3/2 ±9/2   which means that  x  = 3/2 + 9/2  = 12/2  = 6   or   x = 3/2 - 9/2  = -6/2  = -3

 

 

cool cool cool

 Sep 26, 2018

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