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31 votes
31 votes
The sum of the square of a positive number and the square of 2 more than the number is 20. What is the number?

User Aagjalpankaj
by
2.6k points

1 Answer

15 votes
15 votes

Answer:

Let one number = x

Let the other number = x + 2

Use these variables to establish appropriate equations.

x2 + (x + 2)2 = 52

Solve for x from this equation. Expand any terms to get rid of parentheses.

x2 + x2 + 4x + 4 = 52

Combine any like terms.

2x2 + 4x - 48 = 0

WE now have a quadratic equation. Factor out a 2.

2(x2 + 2x - 24) = 0

Factor completely.

2(x + 6)(x - 4) = 0

Set the binomial factors equal to zero.

x + 6 = 0 and x - 4 = 0

Solve for x from these parts. Choose the positive x value.

User Tate Thurston
by
2.7k points
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