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+0  
 
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avatar+979 

Complete the square: \(4x^2+5x+2\).

 

What I tried: 

Plugging in numbers(got nothing)

factoring it(nothing)

using a harry potter wand (nothing, but it was cooler)

sleeping on a cat (cat tried to kill me)

breaking a watch (I don't know the time now)

completing the square (got confused)

 

 Please help me

\(tommarvoloriddle\)

 Jul 5, 2019
edited by tommarvoloriddle  Jul 5, 2019
 #1
avatar
+2

See here:   https://web2.0calc.com/questions/complete-the-square-help_1#r2

 Jul 5, 2019
 #2
avatar+585 
+6

Combine like terms

4x^2+5x=9x^2

9x^2+2=0

solve as a normal problem as 9x+2=0

then 9x=2

divide

x=2/9

x=sqrt(2/9)

 Jul 5, 2019
 #3
avatar+102320 
+2

4x^2 + 5x + 2     factor out the "4"

 

4(x^2 + (5/4)x + 2/4)

 

Take 1/2 of 5/4  =  (1/2)(5/4)  =   5/8 ....square this  = 25/64...add and subtract it within the parentheses

 

4( x^2 + (5/4)x + 25/64  + 2/4 - 25/64)        factor the first three terms, simplify the rest

 

4[ ( x+ (5/8))^2  +  32/64  25/64]

 

4 [ ( x + (5/8) )^2 +  7/64 ]    distribute the4 over the terms inside the parentheses

 

4(x + (5/8))^2  + 28/64

 

4 (x + (5/8))^2  +  7/16

 

 

cool cool cool

 Jul 5, 2019

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