What are the real roots of this equation?

12/x-6+x=3+8x/x-6

A) x = 6
B) x = 7.04 and x = 1.095
C) x = 15 and x = 2
D) x = 15

Respuesta :

ANSWER


The correct answer is [tex]x=15\:or\:x=2[/tex]


EXPLANATION


We have the equation;

[tex]\frac{12}{x-6}+x=3+ \frac{8x}{x-6}[/tex]


We multiply through by the least common multiple, which is [tex](x-6)[/tex].


This gives us;

[tex](x-6) \times \frac{12}{x-6}+x(x-6)=3(x-6)+ \frac{8x}{x-6} \times (x-6)[/tex]


We simplify to obtain;


[tex]12+x(x-6)=3(x-6)+ 8x[/tex]


We now expand to obtain;


[tex]12+x^2-6x=3x-18+ 8x[/tex]


We rewrite the above equation as a quadratic equation in [tex]x[/tex].


This implies that


[tex]x^2-6x-3x-8x+12+18=0[/tex]


This simplifies to;

[tex]x^2-17x+30=0[/tex]


We now split the middle term to obtain;

[tex]x^2-15x-2x+30=0[/tex]


We factor to obtain;


[tex]x(x-15)-2(x-15)=0[/tex]


[tex](x-15)(x-2)=0[/tex]


[tex](x-15)=0\:or\:(x-2)=0[/tex]


[tex]x=15\:or\:x=2[/tex]


Therefore the correct answer is option C








Q&A Education