А) 2y+1x
B)13b+6b+1-b+5=18b+6
C)18a+30-7=18a+23
Корень из 75 расположен между числами 8 и 9
<span>1)
a1=4; an=63; n=16
Sn = </span>(a1+ an)/2*n = (4+63)/2*16=<span>
536
</span>
2)
a1=-1,3; an=-13,7; n=8
Sn = (a1+ an)/2*n = (-1,3-13,7)/2*8=
<span>
-60
</span>
![f(x)= \sqrt{x^2-4}+9\\\\x^2-4 \geq 0\\(x-2)(x+2) \geq 0](https://tex.z-dn.net/?f=f%28x%29%3D+%5Csqrt%7Bx%5E2-4%7D%2B9%5C%5C%5C%5Cx%5E2-4+%5Cgeq+0%5C%5C%28x-2%29%28x%2B2%29+%5Cgeq+0+)
+ - +
____________[-2]____________[2]____________
x∈(-∞;-2]U[2;+∞]