48:8*7=6*7=42
........................
- 2,72 : х= 3,4
х= -2,72: 3,4
х= -0,8
1) cos^2 a = 1- sin^2 a
<span>cos^2 a = 1 - (1/3)^2
</span>cos^2 a = 1 - 1/9
cos^2 a = +- корень (8/9)
соs a = +корень8 / 3
2) <span>log два 32 +logтри27 - 7 = 5 + 3 -7=1
3)</span><span>logдва 16+logпять25-logтри81 = 4 + 2 - 4=2</span>
5,(3)
0,3÷(1-(1/10))=3/10÷9/10=3/10×10/9=3/9
5+3/9=5 цел. 3/9