7x² +18x +5=0x₁*x₂ = 5/7x₁+x₂ = -18/7x₁ = -18/7 - x₂(-18/7 - x₂)*x₂= 5/7-18/7 x₂ - x₂² - 5/7 =0-18x₂ - 7x₂² -5=07x₂² +18x₂ +5 =0D= 18² - 4*7*5 = 324 - 140 =184x₂ =
-18 -√184 =
-18 - 2√46 =
-9 -√46 14 14 7x₂ =
-9 +√46 7При х₂ =
-9-√46 7х₁ =
-18 -
-9-√46 =
-18+9+√46 =
-9 +√46 7 7 7 7При х₂ = -9 +√46х₁ =
-18 +9 -√46=
-9-√46 7 72 способ: более простой7х²+18х+5=0D=18² - 4*7*5=324-140=184x₁ =
-18 -√184 =
-18 - 2√46 =
-9 - √46 14 14 7x₂ =
-9+√46 7