1) 36-21-4=11
2) 47-3+15=59
1)а) х²+4х+1= х²+2х+2х+1=(х+1)²+2х
б) 3b²-12b+11=2b²+b²-6b+9-6b+2=2b²+(b-3) ²+2
<span>в) у</span>²<span>+2у=
у</span>²<span>+2у+1-1= (у+1)</span>²<span>-1</span>
2) а)-b²+6b-8= -(b²-6b+8)= -(b²-4b+2-2b+6)= -( (b<span>-2)</span>²<span>-2</span>b+6)= 2b-6-(b<span>-2)</span><span>²</span>
<span>б)1/4у</span>²<span>-у+2=1/4у</span>²<span>-у+1+1=(1/2у-1) </span>²<span>+1</span>
<span>25-16хВ квадрате=0;
16</span>хВ квадрате=25;
хВ квадрате=25:16;
x=5:4;
x=1,25
Сos²2x + Cos6x - Sin²2x = 0
Cos4x + Cos6x = 0
2Cos5xCosx = 0
Cos5x = 0 или Cosx = 0
5x = π/2 + πk, k ∈Z x = π/2 + πn , n ∈Z
x = π/10 + πk/5, k ∈Z