Произведение равно 0, если хотя бы 1 из множителей равен 0
(5x-1)(0,3x+1,2)(3/7x-42)=0
5х-1=0 5х=1 х=0,2
0,3x+1,2=0 0,3x= -1,2 х= -4
3/7x-42=0 3/7x=42 х=98
(4x+1)(0,2x+8)(3/4x-48)=0
4x+1=0 4х=-1 х= -0,25
0,2x+8 0,2х=-8 х= -40
4x-48=0 4х=48 х=12
<span>{<span><span>4x−x+2y=1</span><span>3−2x=0,2</span></span></span>
Решение.
Начальные преобразования .
<span><span>{<span><span>4x−x+2y=1</span><span>3−2x=0,2</span></span></span>
</span> <span>{<span><span>3x+2y=1</span><span>−2x+3=0,2</span></span></span><span>
{<span><span>3x+2y=1</span><span>−2x+2,8=0
</span></span></span> Решение методом подстановки.
<span><span>{<span><span>3x+2y=1</span><span>−2x+2,8=0</span></span></span>
</span> <span><span>{<span><span>3x+2y=1</span><span>x=1,4</span></span></span>
</span> <span><span>{<span><span>3<span>(<span>1,4</span>)</span>+2y=1</span><span>x=1,4</span></span></span>
</span> <span><span>{<span><span>2y+3,2=0</span><span>x=1,4</span></span></span>
</span> <span><span>{<span><span>y=−1,6</span><span>x=1,4</span></span></span>
</span> <span>{<span><span>y=−1,6</span><span>x=1,4
</span></span></span> Ответ:
<span><span>(<span><span>75</span>;−<span>85</span></span>)</span>=<span>(<span>1<span>25</span>;−1<span>35</span></span>)</span>≈(1,4;−1,6<span>)</span></span>
* ВВЕДЁМ ОБОЗНАЧЕНИЕ : sqrt{70}-квадратный корень из 70
Решение:
(2sqrt{70}-2sqrt{28})/(3sqrt{35}-3sqrt{14})=
=(2sqrt{2*35}-2sqrt{2*14})/(3(sqrt{35}-sqrt{14}))=
=2sqrt{2}(sqrt{35}-sqrt{14})/(3(sqrt{35}-sqrt{14}))=
=2sqrt{2}/3