2,4ч*(v+3км/ч)=19,2км+0,8ч*(v-3км/ч)
2,4ч*v+7,2км=0,8ч*v+19,2км-2,4км
1,6ч*v=9,6км
v=6км/ч
(2a-b)/а^2b-(4a-5b)/ab^2 = (2ab-b^2-4a^2+5ab)/(аb)^2 =
= (7ab-b^2-4a^2)/(аb)^2
X²<span>-3x-40=0
d = b</span>² -4ac = 9 - 4 * (-40) = 9 + 160 = 169
√d = √169 = 13
<u>x₁</u> = ( -b + √d ) / 2a = ( 3 + 13 ) / 2 = 16 / 2 = 8
<u>x₂</u> = ( -b - √d ) / 2a = ( 3 - 13 ) / 2 = -10 / 2 = -5