Решите уравния а) x^2+2x-35=0 б) 5x^2+4x=0

X² + 2x - 35 = 0
D = b² - 4ac = 2² - 4 × 1 × ( - 35) = 4 + 140= 144 = 12²
x₁ = ( - 2 + 12) / 2= 5
x₂ = ( - 2 - 12) / 2 = - 7

5x² + 4x = 0
D = b² - 4ac = 4² - 4 × 5 × 0 = 16 = 4²
x₁ = ( - 4 + 4) / 10 = 0
x² = ( - 4 - 4) / 10 = - 0,8