2x+3x-5=0 (только х в квадрате) x (2x-3) = 4x-3 2 (5x-7) (1+x) = 0 (6-x) (5x+40) = 0

2x^2+3x-5=0

D=3*3+4*5*2=9+40=49=7^2

x1 = - 3+7/4=4/4=1

x2=-3-7/4=-10/4=-2.5

x (2x-3) = 4x-3

2x^2-3x=4x-3

2x^2-3x-4x+3=0

2x^2-7x+3=0

D=49-4*2*3=49-24=25=5^2

x1=7+5/4=12/4=3

x2=7-5/4=2/4=0.5

2 (5x-7) (1+x) = 0

(10x-14) (1+x) = 0

10x+10x^2-14-14x=0

10x^2-4x-14=0

D=4*4+4*14*10=16+560=576=24^2

x1=4+24/20=28/20=1.4

x2=4-24/20=-20/20=-1