1)2x(5x-7)=2x^2-5
10x^2-14x-2x^2+5=0
8x^2-14x+5=0
D=(-14)^2-4×8×5=196-160=36
x1=14+6/16=20/16=5/4=1,25
x2=14-6/16=8/16=1/2=0,5
2)(x+4)^2=4x^2+5
x^2+8x+16-4x^2-5=0
-3x^2+8x+11=0×(-1)
3x^2-8x-11=0
D=(-8)^2-4×3×(-11)=64+132=196
x1=8+14/6=22/6=11/3=3 2/3
x2=8-14/6=-6/6=-1
3)(x-5)^2=3x^2-x+14
x^2-10x+25-3x^2+x-14=0
-2x^2-9x+11=0×(-1)
2x^2+9x-11=0
D=9^2-4×2×(-11)=81+88=169
x1=-9+13/4=4/4=1
x2=-9-13/4=-22/4=5,5
4)9x(4x-1)=3x-1
36x^2-9x-3x+1=0
36x^2-12x+1=0
D=(-12)^2-4×36×1=144-144=0
x1=12+0/72=1/6
x2=12-0/72=1/6