Question

Solve the square of this equation with explanation as I don’t understand please

Answer 1

Answer: The two solutions are x = -4 and x = -6

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Explanation:

Cut the x coefficient (10) in half to get 10/2 = 5. Then square this to get 5^2 = 25.

We'll add 1 to both sides so that the "24" turns into "25", thereby completing the square

x^2 + 10x + 24 = 0

x^2 + 10x + 24+1 = 0+1

x^2 + 10x + 25 = 1

Notice on the left hand side we have something of the form A^2+2AB+B^2 where A = x and B = 5. We can factor this into (A+B)^2, which is the whole reason why we completed the square. You can use the FOIL rule to see how (A+B)^2 expands out into A^2+2AB+B^2. Factoring reverses this process.

This means x^2+10x+25 factors to (x+5)^2 and we now have these steps

(x+5)^2 = 1

x+5 = sqrt(1) or x+5 = -sqrt(1)

x+5 = 1 or x+5 = -1

x = 1-5 or x = -1-5

x = -4 or x = -6 are the two solutions

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Let's check x = -4 to see if it works or not

x^2 + 10x + 24 = 0

(-4)^2 + 10(-4) + 24 = 0

16 - 40 + 24 = 0

-24 + 24 = 0

0 = 0

We get a true equation. That confirms x = -4 is a solution.

If we tried x = -6, then,

x^2 + 10x + 24 = 0

(-6)^2 + 10(-6) + 24 = 0

36 - 60 + 24 = 0

-24 + 24 = 0

0 = 0

That x value is confirmed as well.