1. b/ac ---> (-1,5)/(2*0,9)=(-3/2)/(2*(9/10)=(-3/2)/(9/5)=(-1/2)/3/5)=(-5/6)
2. 6a+(4a-7)-(a+3)=6a+4a-7-a-3=9a-10
3. 1:4=5x:8
8=20x
x=8/20
x=2/5
x^2-2x+2=<span> x^2-2x+1-1+2=(x-1)</span>²+1
min=1 (x=1)
![5x^2-7x+2=0 \\ D=49-40=9 \\ x_1=(7-3)/10=1/2 \\ x_2=(7+3)/10=1](https://tex.z-dn.net/?f=5x%5E2-7x%2B2%3D0+%5C%5C+D%3D49-40%3D9+%5C%5C+x_1%3D%287-3%29%2F10%3D1%2F2+%5C%5C+x_2%3D%287%2B3%29%2F10%3D1)
наименьший корень 1/2, то есть 0.5
√(36×1,21)=6×1,1=6,6; √(3 6/25×2 2/49)=9/5 ×10/7 =18/7=2 4/7; √(15×10×6)=30; √2,7 × √120=18; √5 / √500 =1/√100 =1/10