Respuesta :

Answer:

20x²+180x + 405

Step-by-step explanation:

Follow PEMDAS to know what you do first

square (2x + 9) by foiling

(2x+9) (2x + 9)

= 4x²+ 36x + 81

Multiply by 5

20x²+180x + 405

Answer:

20x^2 + 180x +405

Step-by-step explanation:

5(2x+9)²

5 ( 2x+9) (2x+9)

FOIL

first

2x*2x = 4x^2

outer: 2x*9 = 18x

inner 2x*9 = 18x

last : 9*9 = 81

Add these together :  4x^2 + 18x+18x +81  = 4x^2+36x+81

5( 4x^2+36x+81 )

20x^2 + 180x +405