(25а^2 - 40a + 16) -(6a^2 + 14a - 3a - 7) = 19a^2 - 51a + 23
Общий знаменатель 6
2 - 7х + 2( 4х + 7 ) = - 6х
2 - 7х + 8х + 14 = - 6х
Х + 16 = - 6х
7х = - 16
Х = - 16/7 = - 2 2/7
1) a10=sqrt(a9*a11)=sqrt(15*135)=45
2)a2=a1*q a6=a1*q^5 a2*a6=a1^q6=a1^q3*a1*q^3=a4^
a2*a6=144
3) a5*a7=a6*a6 a6/a8=1/q^=1/(1/2)^=4
4) -18/36=-1/2
S=b1/(1-q)=36/(1+1/2)=24
X² - 8x - 1 = 0
D = b² - 4ac
D = (-8)² - 4 × 1 × (-1) = 64 + 4 = 68
x₁,₂ = 8 ₊/₋√68 / 2