Y=x²-8x+5=(x-4)²-11
Парабола у=х²,ветви вверх,вершина (4;-11)-точка минимума
Убыв x∈(-∞;4)
Возр x∈(4;∞)
<span> 4.</span><em>2х</em><span>2 - 18x + 40 = 0; 2у2 + у - 7 = 0; 0,</span><em>5 х</em><span>2 + 3x - 8 = 0. 2. </span>...<span> 4 и -3; -</span><em>6</em><span> и </span><em>5</em><span>; 2 - и 2 + . 3.</span>...<span> Дано: ах2 + bx + c = 0, где а = </span><em>1</em><span>, x</span><em>1</em><span> и x2 –корни квадратного уравнения</span>
<span>
а) (6а+1)(6a+1)</span>
<span />б)(10х+7у)(10х-7у)
<span>в)(5х-2у)(25х<span>²+10ху+4у<span>²</span></span>)</span>
<span>г)(у3+1</span><span>)(у-1)</span>
18 : ( 10 + Х) + 14 : ( 10 - Х) = 3,25
18 * ( 10 - X) + 14 * ( 10 + X) = 3,25 * ( 100 - X^2 )
180 - 18X + 140 + 14X = 325 - 3,25X^2
320 - 4X = 325 - 3,25X^2
- 3,25X^2 + 4X + 5 = 0
D = 16 + 65 = 81
V D = 9
X1 = ( - 4 + 9 ) : ( - 6,5 ) = ( - 0,769)
X2 = ( - 13 ) : ( - 6,5) = + 2
Ответ 2 км/час