18. \( 3 x(x-11)=0 \) 19. \( x^{2}-14 x=-40 \) 20. \( -8 x-12>4 \)

To solve the first equation \( 3 x(x-11)=0 \), you can set each factor equal to zero: \( 3x = 0 \) or \( x - 11 = 0 \). This gives you \( x = 0 \) or \( x = 11 \). For the second equation \( x^{2}-14 x=-40 \), you rearrange it to standard form: \( x^{2}-14 x + 40 = 0 \). You can factor this as \( (x-4)(x-10)=0 \), leading to solutions \( x = 4 \) or \( x = 10 \). For the inequality \( -8 x-12>4 \), first, add 12 to both sides to get \( -8x > 16 \). Then, divide by -8, remembering to flip the inequality sign: \( x < -2 \). So the solution indicates values less than -2!