Question

Докажите,что значение выражения (4x-1)(5x-2)-(4x+1)(5x+2)+26x+3 не зависит от значений x

Answer 1

$(4x-1)(5x-2)-(4x+1)(5x+2)+26x+3=\\= [(4x-1)(5x-2)]-[(4x+1)(5x+2)]+26x+3=\\= [4x*(5x-2)-(5x-2)]-[4x*(5x+2)+(5x+2)]+26x+3=\\= [20x^2-8x-5x+2]-[20x^2+8x+5x+2]+26x+3=\\= 20x^2-8x-5x+2-20x^2-8x-5x-2+26x+3=\\= -16x-10x+26x+3=3$