Question

100 points please help me asap!!

Answer 1

Answer:

$(x+5)^2=4$

Step-by-step explanation:

We have:

$x^2+10x+21=0$

First, subtract 21 from both sides:

$x^2+10x=-21$

Now, we can complete the square. We will divide the coefficient of the b term and square it. So:

$(\frac{b}{2})^2\Rightarrow(\frac{10}{2})^2=(5)^2=25$

So, we will add 25 to both sides:

$(x^2+10+25)=-21+25$

The left is the perfect square trinomial pattern. Add on the right:

$((x)^2+2(5)(x)+(5)^2)=4$

Final step:

$(x+5)^2=4$