(3x+4)(4-3x)-(2x+1)^2

Question

(3x+4)(4-3x)-(2x+1)^2

Answer 1

(4 + 3x)(4 - 3x) - (2x + 1)^2 = 
= 16 - 9x^2 - (4x^2 + 4x + 1) = 
= 16 - 9x^2 - 4x^2 - 4x - 1 =  
= - 13x^2 - 4x + 15