2y^2-7y+6=0 7x^2-34x-5=0 5y^2+3y=0 x^2-2x-3=0 7c^2+13c-2 - вопрос №6097309227607234505230223072132 от laf03 25.12.2020 18:07

Question

Алгебра: 2y^2-7y+6=0 7x^2-34x-5=0 5y^2+3y=0 x^2-2x-3=0 7c^2+13c-2 решить уравнения и найти корни,

laf03 · Answer

1) 2y² -7y +6 =0D =49 -4×2×6=1x1 =(7 -1)/4 =6/4=1.5x2 =(7+1)/4 =2ответ: x =1.5; x =22) 7x² -34x -5 =0D =34² +4×7×5=1296=36²x1 =(34 -36)/14 = -2/14 = -1/7x2 =(34 +36)/14 =5ответ: x = -1/7; x =53) 5y² +3y =0y(5y +3)=0y =05y +3=0y = -3/5 = -0.64) x² -2x -3 =0D =4 +4*3 =16 =4²x1 =(2 -4)/2 = -1x2 =(2+4)/2=35) 7c² +13c -2 =0D =13² +4*7*2 =225 =15²x1 =(-13 -15)/14 = -2x2 =(-13 +15)/14 =2/14 =1/7...