Factor 4y^2-20y+25

$4 y^{2} - 20 y + 25$

Step 1

Rewrite $4 y^{2}$ as ${(2 y)}^{2}$ .

${(2 y)}^{2} - 20 y + 25$

Step 2

Rewrite $25$ as $5^{2}$ .

${(2 y)}^{2} - 20 y + 5^{2}$

Step 3

Check that the middle term is two times the product of the numbers being squared in the first term and third term.

$20 y = 2 \cdot (2 y) \cdot 5$

Step 4

Rewrite the polynomial.

${(2 y)}^{2} - 2 \cdot (2 y) \cdot 5 + 5^{2}$

Step 5

Factor using the perfect square trinomial rule $a^{2} - 2 a b + b^{2} = {(a - b)}^{2}$ , where $a = 2 y$ and $b = 5$ .

${(2 y - 5)}^{2}$