+{7x+3y=43
+{4x-3y=67
11x=110|:11
x=10
4*10-3y=67
-3y=67-40
-3y=27|:(-3)
y=-9
Решение. Способ 1<span><span>f′</span>(x)=<span><span>(<span><span>4⋅x−7 / </span><span>x2</span></span>)</span>′</span>=
</span><span>=(<span><span><span><span>(4⋅x−7)</span>′</span>⋅<span>x2</span>−<span>(4⋅x−7)</span>⋅<span><span>(<span>x2</span>))</span>′ / </span></span><span><span>(<span>x2</span>)</span>2</span></span>=
</span><span>=<span><span><span><span>(4⋅x)</span>′</span>⋅<span>x2</span>−<span>(4⋅x−7)</span>⋅2⋅x</span><span><span>(<span>x2</span>)</span>2</span></span>=
</span><span>=<span><span>4⋅<span>x2</span>−<span>(4⋅x−7)</span>⋅2⋅x / </span><span><span>(<span>x2</span>)</span>2
</span></span></span>Ответ:<span>f′</span>(x)=<span><span>4⋅<span>x2</span>−<span>(4⋅x−7)</span>⋅2⋅x / </span><span><span>(<span>x2</span>)</span><span>2</span></span></span>
Легче этого ничего не решала:)
1.б)6х-10,2=0
6x=0+10,2
6x=10,2
x=10,2:6
x=1,7
5x-4,5=3x+2,5
5x-3x=2,5+4,5
2x=7
x=7:2
x=3,5
2x-(6x-5)=45
2x-6x+5=45
-4x=45-5
-4x=41
2.x+(x+6)=26
2x+6=26
2x=26-6
2x-20
x=20:2
x=10(мин)-едет на автобусе
10+6=16(мин.)-идёт пешком
3.3x-20=x+10
3x-x=10+20
2x=30
x=30:2
x=15(т.)-во втором сарае
15*3=45(т.)-в первом
7x-(x+3)=3(2x-1)
7x-x-3=6x-3
7x-x-6x=-3+3
0=0