<span>25-(13+ t)² = 0;</span>
25-(169+26t+t²) = 0;
25-169-26t-t² = 0;
-t²-26t-144 = 0;
D = b²-4ac = 676-4*(-1)*(-144) = 100.
t1 = -b+√D/2a = 26+10/(-2) = 36/(-2) = -18;
t2 = -b-√D/2a = 26-10/(-2) = 16/(-2) = -8.
Ответ: t1 = -18; t2 = -8.
Числа 16,17,18 ну или же -16,-17,-18
0,2(X-3)=0,4(7-X)-4,6
0,2X-0,6=2,8-0,4X-4,6
0,2X-0,6+1,8+0,4X=0
0,6X+1,2=0
0,6X=-1,2
X=-2