Almoquiraidn
Answered

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quadratic equation by completing the square?
1) 5x^2-25x-70=0

Sagot :

Raquelidn
5x^2 -25x -70 = 0

1/5 [5x^2 -25x -70 = 0] 1/5

x^2 -5x -14 = 0

x^2 -5x +[1/2(-5)]^2 = 14 +[1/2(-5)]^2

x^2 -5x +(25/2) = 14 + (25/2)

(x-5/2)(x-5/2) =56/4 +25/4

(x-5/2)(x-5/2) =81/4

the square root of (x-5/2)^2 = the square root of 81/4

x-5/2= the positive or negative 9/2

x-5/2=9/2                     x-5/2=-9/2
x=5/2+9/2                    x=5/2-9/2
x=14/2                          x=-4/2
the root 1                    the root 2 is 2
is 7

i hope it will help you,,good evening :)



Omneslalaineidn
[tex]5x^2-25x-70=0 [/tex]
[tex](5x-35)(x+2)=0[/tex]

[tex]5x-35=0[/tex]
[tex]5x=35[/tex]
[tex]5x/5=35/5[/tex]
[tex]x=7[/tex]

[tex]x+2=0[/tex]
[tex]x=-2[/tex]


[tex]x= \left \{ {{7} \atop {-2}} \right. [/tex]


Hope it helps! :)