А)11x^2-6x-27=8x^2-6x
11x^2-6x-8x^2+6x-27=0
3x^2-27=0
3x^2=27
x^2=9
x=+- корень из 9
х=+3;-3
б)26+5у-0,5y^2-2,5y^2-26=0
5y-3y^2-0
y(5-3y)=o
y=0 или 5-3y=0
-3y=-5
y=5/3
Ответ: x∈[3/5;3]
Объяснение:√5x-3 +√3-x -- имет смысл,если 5х-3≥0 и 3-х≥0,решим как
систему неравенств {x≥3/5, x≤3
А₅ = а₁ +4d
a₇ = a₁ +6d
а₁ +4d = 9
a₁ +6d = 13
a₁ = 9- 4d
9- 4d +6d =13
2d=13-9
d=4:2
d=2
a₁ = 9-4*2 = 9-8=1
a₃₀ = a₁ +29d
a₃₀ = 1 +29*2 = 1+58 =59
Ответ: a₃₀ = 59
(1/3*1/2m+1/3*(-3)-m*1/2m-m*(-3)
(1/3*1/2m+1*(-1)-m*1/2m-m*(-3)
(m/2*3+1*(-1)-m*1/2m-m*(-3)
1/6m+1*(-a)-m=1/2m-m*(-3)
(1/6m-1-m*1/2m-m*(-3)
(1/6m-1-1/2m^2-m*(-3)
(1/6m-1-1/2m^2+3m)
(-1/2m^2+1/6m+3m-1)
(-1/2m^2+1/6m+3m*6/6-1)
(-1/2m^2+1/6m+18m/6-1)
(-1/2m^2+1/6(m+18m)-1)
(-1/2m^2+19m/6-1)
-1/2m^2+19m/6-1 ответ!