6,5a + a + 2.2 = 17.2
7.5a = 17.2 - 2.2
7.5a = 15
a = 15 : 7.5
a = 2
Ответ: 2
<span>a₆=30-5*10=-20
или
</span><span>а6=30+(-10)*5=30-50=-20</span>
F'(x) = 5/(2√(5x +4))
5/(2√(5x +4)) = 0,3125
5/(2√(5x +4)) =5/16
1/(√(5x +4)) = 1/8
√(5х+4) = 8
5х +4 = 64
5х = 60
х = 12