(2√7)^2+12√7+9=28+12√7+9=37+12√7
0,16aˇ4-0,09b²=(0,4a²)²-(0,3b)²=(0,4a²+0,3b)(0,4a²-0,3b)
А₃=6 d=1
A₆-?
1 способ:
А₆=А₃+3d=6+3*1=9
2 способ:
А₃=А₁+2d
6=A₁+2*1
A₁=6-2=4
A₆=A₁+5d=4+5*1=9
3/4 = 0.75( так удобно считать)
1.2*(0.5х -2) -0.6х= 0.75х+1.83
0.6х-2.4-0.6х=0.75х+1.83
0.6х-0.6х-0.75х=1.83+2.4
-0.75х=4.23
х=-5.64