![a)\; \; 2x^2+3x+5=0\\\\D=9-4\cdot 2\cdot 5=9-40=-31<0\; \; \Rightarrow](https://tex.z-dn.net/?f=a%29%5C%3B+%5C%3B+2x%5E2%2B3x%2B5%3D0%5C%5C%5C%5CD%3D9-4%5Ccdot+2%5Ccdot+5%3D9-40%3D-31%3C0%5C%3B+%5C%3B+%5CRightarrow)
действительных корней нет
![b)\; \; 2x^2-5x+2=0\\\\D=25-4\cdot 2\cdot 2=9>0\; \; \Rightarrow](https://tex.z-dn.net/?f=b%29%5C%3B+%5C%3B+2x%5E2-5x%2B2%3D0%5C%5C%5C%5CD%3D25-4%5Ccdot+2%5Ccdot+2%3D9%3E0%5C%3B+%5C%3B+%5CRightarrow)
Квадратное уравнение имеет ровно два действительных корня.
![x_1=\frac{5-3}{4}=\frac{2}{4}=\frac{1}{2}\; \; ,\; \; x_2=\frac{5+3}{4}=\frac{8}{4}=2](https://tex.z-dn.net/?f=x_1%3D%5Cfrac%7B5-3%7D%7B4%7D%3D%5Cfrac%7B2%7D%7B4%7D%3D%5Cfrac%7B1%7D%7B2%7D%5C%3B+%5C%3B+%2C%5C%3B+%5C%3B+x_2%3D%5Cfrac%7B5%2B3%7D%7B4%7D%3D%5Cfrac%7B8%7D%7B4%7D%3D2)
Q=3:6 = 1/2
b4 = b1*q³ = 6*1/8 = 6/8= 3/4
S5 = b4(q^5-1)/(q-1) =
=3/4*(1/32-1)/(1/2 -1) = 3/4*(-31/32): (-1/2)= 3/4*31/32*2/1)= =93/64
Ответ: 64*S = 64*93/64 = 93
Разделим на√2:
1/√2 · sin3x - 1/√2 · cos3x = sinx
sin(3x - π/4) = sinx
sin(3x - π/4) - sinx = 0
2cos(2x - π/8) · sin(x - π/8) = 0
cos(2x - π/8) = 0 sin(x - π/8) = 0
2x - π/8 = π/2 + πn x - π/8 = πk
2x = 5π/8 + πn x = π/8 + πk
x = 5π/16 + πn/2
Надеюсь что все верно решено)))
1) х+16=32
х=32-16
х=16
2) 28+у=158
у=130
3)2з=76-34
з=17
4) 15у=75
у=7
5) 161х=322
х=2
6)7у=70
у=10
7)4х=130-70
4х=60
х=15
8)3х=15
х=5
9)9у=144
у= 16
10)8з=72
з=9
11)48-х=8
х= 40