1-х,2-х+1.3-х+2,4-х+3 х=792
[[(x+3)]*[9x+2)(x+1)]+1=(x²+3x)(x²+3x+2)+1=(x²+3x)²+2(x²+3x)+1=
=(x²+3x+1)²=(792²+3*792+1)²=(627264+2376+1)²=629641²
2х-1=8
2х=9
х=4,5
2х-1=-5
2х=-4
х=-2
(x²-4x)²-(x²-4x+4)-16≤0
(x²-4x)²-(x²-4x)-20≤0
x²-4a=a
a²-a-20≤0
a1+a2=1 U a1*a2=-20
a1=-4 u a2=5
-4≤a≤5
{x²-4x≥-4 (1)
{x²-4x≤5 (2)
(1) x²-4x+4≥0
(x-2)²≥0⇒x-любое
(2) x²-4x-5≤0
x1+x2=4 u x1*x2=-5⇒x1=-1 U x2=5
x∈[-1;5]
АВ/sinC=AC/sinB
AC=AB•sinB/sinC=12•0.4/0.12=40 см.
А7=а1+d*(n-1)
a7=15+(-6)*6
а7=-21