2) 1.5(X-6)=1.4(X+5)
1.5X-9=1.4X+7
0.1X=16
X=160
1) 0.7X-3.5=X-0.1
0.7X-X=3.5-0.1
-0.3X=3.4
X= -11.333(3)
2,3a-0,7a+3,6a-1=5,2а-1
<span>
0,48b+3+0,52b-3,7b
=-2,7b+3</span>
<span><span>(a+3)2</span>−2a(3−4a)</span> = a2+6a+9-6a+8a2=9a2+9=9(a2+1)
<span>a=−<span>13
9(169+1)=9*170=<u>1530</u></span></span>
Сtgx=0
x=π/2+∈z
-π≤π/2+πn≤π/2
-2≤1+2n≤1
-3≤2n≤0
-1,5≤n≤0
n=-1⇒x=π/2-π=-π/2
n=0⇒x=π/2
-π/2+π/2=0