Вот, держи решение. Надеюсь, помогла :)
Преобразуем 1 ур-е преобразуем 2 ур-е
(2х-4у)*3 = (4х+6у)*5 6(х+у) = 4(у-2)
6х-12у = 20х+30у 6х+6у = 4у-8
6х-12у-20х-30у = 0 6х+6у-4у+8 = 0
-14х-42у = 0 6х+2у+8 = 0
3х+у+4 = 0
получили систему
-14х-42у=0
3х+у+4=0
выражаем из 2 ур. у
у=-3х-4 и подставляем в 1 ур.
-14х-42(-3х-4) = 0
-14х+126х+168 = 0
112х = -168
х = -1,5
подставляем в у
у = -3(-1,5)-4 = 4,5-4 = 0,5
<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>