1. = sin(a)cos(a)-sin(a)sin(a)=sin(a)cos(a)-sin(a²)
2. a) sin10°+cos40°=sin10°+cos(90°-50°)=sin10°+sin50°=2sin30°cos(-20°)=2**cos20°=cos20°
б) tg40°+ctg20°=tg40°+tg70°=
3. =
3×1−4÷5−2×2.5
=−2.8 .......
<span>1)
√125 + √245 - √80 =
</span>= √(25·5) + √(49·5) - √(16·5) =<span>
= 5</span>√5 + 7√5 - 4√5 = 8√5
Ответ: <span>8</span>√5
<span>
2)
3√192 - 0,1√48 - </span>²<span>/</span>₃ <span>√27 =
= 3</span>·√(64·3) - 0,1·√(16·3) - ²/₃ ·√(9·3) =
= 3·8√3 - 0,1·4√3 - ²/₃ ·3√3 =
= 24√3 - 0,4√3 - 2√3 = 21,6√3
Ответ: 21,6√3
8x+6-(7x+4)=5
x+2=5
x=5-2
<span>x=3</span>