Question

Решите уравнение: (7х + 1)(x - 3) + 20(х - 1)(х + 1)= 3(3х - 2)2 + 13.

Answer 1

(7х + 1)(x - 3) + 20(х - 1)(х + 1)= 3(3х - 2)2 + 13

7x²-21x+x-3+20(x²-1)=3(9x²-12x+4)+13
7x²-20x-3+20x²-20-27x²+36x-12-13=0
16x-48=0
16x=48
x=3