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Dimitri is solving the equation x2 – 10x = 21. Which value must be added to both sides of the equation to make the left side a perfect-square trinomial?

User Lyon
by
7.3k points

2 Answers

6 votes

Answer:

25.

Explanation:

To find the value that will make the left side a perfect-square trinomial, you need to find (b/2)^2. In this case, b = -10.

(-10 / 2)^2

= (-5)^2

= (-5) * (-5)

= 25

Once you add 25 to both sides, the left side becomes x^2 - 10x + 25, which is equal to (x - 5)^2.

Hope this helps!

User JKL
by
7.7k points
6 votes

Answer:


\boxed{\sf \ \ 25 \ \ }

Explanation:

Hello,

we can see that


x^2-10x = x^2-2*5x

is the beginning of


x^2-2*5x+5^2=(x-5)^2

so we must add 5*5=25 to both sides of the equation to make the left side a perfect square trinomial

hope this helps

User Onthemoon
by
7.7k points