How do you multiply (x + 5)^2?

1 Answer
Sep 7, 2016

x^2 +10x+25

Explanation:

Squaring means multiplying a factor or term by itself,
This example is called squaring a binomial
The answer is a trinomial

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

color(red)("DO NOT JUST SQUARE EACH TERM INSIDE!!")

Each term in the bracket must be multiplied by each term in the second bracket,

(x+5)^2 = x^2 color(blue)(+5x+5x)+25 = x^2 +10x+25

Note: the two middle terms will ALWAYS be the same

color(blue)(+5x+5x = 10x)

Can you see the short method to get to the answer?

(2x - 3)^2 = 4x^2-12x+9

5x^2 -3y)^2 = 25x^4 -30x^2y +9y^2