-12<3x+15<21
3x>-12+15<21
3x>3<21
3x<21-3
3x<18
x<18÷3
x<6
(у - 6,5) : 7 = 0,5
y - 6,5 = 0,5 * 7
y = 3,5 + 6,5
y = 10
8,4 : (у - 2) = 4
y - 2 = 8,4 : 4
y = 2,1 + 2
y = 4,1
1. 7(2х-3)+(3х-2)=14х-21+3х-2=17х-23
2. -2(4х+8)-3(5к-1)=-8х-16-15к+3=-8х-13-15к
3. -8(2-2у)+4(3-4у)=-16+16у+12-16у=-4
4. (3х-11)*2-5(4-3х)=6х-22-20+15х=21х-42
<span>а)360°=2*180</span>°=2π<span>;
180°=</span>π<span>;
90°=90</span>°*π/180=π/2<span>;
270°=270*</span>π/180=3π/2<span>;
0°=0
б)45°=45</span>°*π/180=π/4<span>;
135°=135*</span>π/180=3π/4<span>;
225°=225*</span>π/180=5π/4<span>;
315°=315*</span>π/180=7π/4<span>;
в)60°=60*</span>π/180=π/3<span>;
120°=120*</span>π/180=2π/3<span>;
240°=240*</span>π/180=4π/3<span>;
300°=300</span>π/180=5π/3<span>;
г)30°=30*</span>π/180=π/6<span>;
150°=150*</span>π/180=5π/6<span>;
210°=210*</span>π/180=7π/6<span>;
330°=330*</span>π/180=11π/6<span>;
д)-45°=-45*</span>π/180=-π/4<span>;
-90°=-90*</span>π/180=-π/2<span>;
-135°=-135*</span>π/180=-3π/4<span>;
-180°=-</span>π<span>;
е)-270°=-270*</span>π/180=3π/2<span>;
-360°=2*180=2</span>π<span>;
-1800°=1800*</span>π/180=10π