The teacher will be very surprised to see your correct solution 😉
3*x 2*x*(3 + 8*x) - (4*x - 3)*(4*x + 3) = --- 2
2*x*(3+8*x)-(4*x-3)*(4*x+3) = (3/2)*x
6*x + 16*x^2 - (4*x - 3)*(4*x + 3) = (3/2)*x
6*x + 16*x^2 + 9 - 16*x^2 = (3/2)*x
2*x*(3+8*x)-(4*x-3)*(4*x+3) = 3*x/2
9 + 9*x/2 = 0
x = -9 / (9/2)