To begin with you multiply each term in the parentheses by each term in the second parentheses in the equation So then it would be
4x • 5x+4x • 2 + 4 • 5x+4 • 2
That then when you calculate it it would be
20x^2+8x+20x+8
Then you get the like terms.
20x^2+28x+8
