√(6*40)*√90=√6*40*90=√6*√3600=<u>60√6</u>
(n-2)*(n-1)-(n-3)n
док - во:
n квадрат+3-(n квадрат - 3n)
n квадрат+3-n квадрат+ 3n
3+3n
б)<span> ℓog2x+3(5x2+11x+3)=2</span>
<span>5x²+11x+3=(2x+3)²</span>
<span>5x²+11x+3=4x²+12x+9</span>
<span>5x²+11x+3-4x²-12x-9=0</span>
<span>x²-x-6=0</span>
<span>D = 1²-4*1*(-6)=1+24=25</span>
<span>x1=(1+5)/2=3</span>
<span>x2=(1-5)/2=-2</span>
B2=3×10=30; B3=30×10=300; B4=b4-1×q=B3×q=3000