-8,29k+(6,4−6)= -4+6,4−8,49k = -8,29k + 0,4 = -4 + 6,4 - 8,49k = -8,29k + 0,4 = 2,4 - 8,49k = -8,29k + 8,49k = 2,4 - 0,4 =0,2k =2 = k = 10
<span>(2a-b)(2a+b)+b^2=4a^2-b^2+b^2=4a^2</span>
<span><span>(x+7)^2-10x= x^2+14x+49-10x=x^2+4x+49</span></span>
<span><span><span>9x^2 - (c+3x)(c-3x)=9x^2-(c^2-9x^2)=9x^2-c^2+9x^2=18x^2-c^2</span></span></span>
<span><span><span><span>5b^2-(a-2b)^2=5b^2-(a^2-4ab-4b^2)=5b^2-a^2+4ab+4b^2=9b^2-a^2+4ab</span></span></span></span>
V, км/ч t,ч S, кмПо теч 30+х 7 7(30+x)Против теч 30-х 8 8(30-x)