the square of the sum of a number and 2 is equal to the sum of the number and 4. What is the number?​

Sagot :

Answer and step-by-step explanation:

To find the number, translate the given statement to an algebraic expression first.

Let n be the number.

[tex](n + 2) {}^{2} = n + 4[/tex]

Then simplify the left side of the equation by using the FOIL method.

(n+2)(n+2)

F: n × n = n^2

O: n × 2 = 2n

I: 2 × n = 2n

L: 2 × 2 = 4

= n^2 + 2n + 2n + 4

= n^2 + 4n + 4

Then move n and 4 to the left side of the equation by subtracting them to both sides of the equation.

n^2 + 4n - n + 4 - 4 = n - n + 4 - 4

n^2 + 3n = 0

Then factor the polynomial by dividing them by their GCF which is n.

n(n + 3) = 0

Then equate the two factors to 0.

n = 0

n + 3 = 0

n + 3 - 3 = -3

n = -3

Then check by substituting the values of n to the equation.

(0 + 2)^2 = 0 + 4

4 = 4

(-3 + 2)^2 = -3 + 4

1 = 1

Both equations are true.

The numbers are 0 and -3.