Question

5х квадрад-х-42=0
5х квадрад+9х+4=0

Answer 1

1)  5x² - x - 42 = 0
D = 1 + 4*5*42 = 841
x₁ = (1 - 29)/10
x₁ = - 2,8
x₂ = (1+ 29)/10
x₂ = 3
2)  5x₂ + 9x + 4 = 0
D = 81 - 4*5*4 = 1
x₁ = (- 9 - 1)/10
x₁ = - 1
x₂ = (- 9 + 1)/10
x₂ = -8/10
x₂ =  - 4/5