Solve x2 + 8x – 48 = 0 by completing the square. Show your work for full credit.

Question

radar · Answer

For completing the square the coefficient of the "squared" term should be 1 and it is.

radar · Answer

The term to be added to make it a perfect square is one half of the coefficent of the x term squared.

radar · Answer

What you add you must also subtract to retain the equations original value.

anonymous · Answer

$$(x^2+8x+16)-16-48$$ <---- just added and substracted 4, which is $$(8/2)^2$$

Now try to factor out the term in brackets what do you get?

radar · Answer

Lets see how saljudieh07 did this

radar · Answer

Looks good.

anonymous · Answer

sorry $$4^2$$ that is what I added and substracted

anonymous · Answer

now, kaymarie12479 can you factor the expression in the brackets?

radar · Answer

Actually you want to the square root of the value in the brackets.  The origiinal equation is factorable, but you want to "complete the square.
$$(x + 4)^{2}=64$$

radar · Answer

$$x+4=\pm8$$

radar · Answer

Note the original equation is factorable (x-4)(x+12)=0   however, they want you to use completing the square method.

radar · Answer

Note.  That factoring gives you x=4 and x=-12 as answer
and
x + 4 = +/- 8
gives same results x=4, and x=-12

radar · Answer

@saljudieh07 you left off the "=0" and disregarded your constants.