1)
5,25 - 4 21/40 =29/40
2)
7 1/3 - 6,875 = 11/24
3)
29/40 : 1,45 = 1/2
4)
11/24 : 0,75 = 11/18
5)
1/2 - 11/28 = 3/28
<span><span>{<span><span>4x−3y=12
</span><span><span>4/3</span>x−y=4</span></span></span>⇒
</span><span><span>
{<span><span>4x−3y=12
</span><span>y=<span>43</span>x−4</span></span></span>⇒
</span><span><span>
{<span><span>4x−3<span>(<span>43</span>x−4)</span>=12
</span><span>y=<span>43</span>x−4</span></span></span>⇒
</span><span><span>
{<span><span>0=0</span><span>y=<span>43
</span>x−4</span></span></span>⇒
</span><span>Получили верное равенство для любого </span>xОтвет: <span><span>(x;<span>43</span>x−4),x∈R</span></span>
х=0
0,5 * 0 - 0 +1 = 1
х=-1
0,5 * 1 - 1+1=0,5
х=-2
0,5 * 4 - 2 +1=1
х=4
0,5*16-4+1=5
<span>1.</span>
<span> у=5х²-4х-4</span>
5х²-4х-4=<span>-3</span>
<span>5х²-4х-1=0</span>
<span>D=b²-4ac=16-4*5*(-1)=36 корень из D=6</span>
х1=4+6/10=1
х2=4-6/10=-0,2
2.
5х²-4х-4=8
5х²-4х-12=0
D=b²-4ac=16-4*5*(-12)=256 корень из D=16
x1=4+16/10=2
х2=4-16/10=-1,2
Возможно первое так, или другое пришлю