А)х^3-4xy^2=x(x^2-4y^2)=x(x-2y)(x+2y)
б)(a^2-ab)+7a-7b=a(a-b)+7(a-b)=(a+7)(a-b)
=7-18y+12=-18y+19
-18y=-19
y=19/18
А) а3 - 2а2 + 2а - 4 = а2 • (a - 2) + 2 • (a - 2) = (а2<span> + 2)(a - 2); </span>
б) х3 - 12 + 6х2 - 2х = х2 • (x + 6) - 2 • (x + 6) = (х2<span> - 2)(x + 6); </span>
в) с4 - 2с2 + с3 - 2с = с3 • (c + 1) - 2c • (c + 1) = (с3<span> - 2c)(c + 1); </span>
г) -у6 - у5 + у4 + у3 = -у5• (y + 1) + y3<span> • (y + 1) = (y</span>3<span> - у</span>5)(y + 1);
д) а2b - b2с + а2с - bc2 = а2 • (b + c) - bc • (b + c) = (а2<span> - bc)(b + c); </span>
е) 2х3 + ху2 - 2х2у - у3 = 2х2 • (x - y) + y2<span> • (x - y) = = (2х</span>2<span> + y</span>2)(x - y);
ж) 16аb2 - 10с3 + 32ас2 - 5b2с = 16a • (b2<span> + 2c</span>2) - 5c • (b2<span> + 2c</span>2) = (16a - 5c)(b2<span> + 2c</span>2<span>); </span>
з) 6а3 - 21а2b + 2аb2 - 7b3 = 2a • (3а2<span> + b</span>2) - 7b • (3а2<span> + b</span>2) = (2a - 7b)(3а2+ b2<span>).</span>
П радиан - 180°
3/5 радиан - х°
х°=180°*(3/5):П=108:П≈108:3,14=34,39°
cos3/5≈cos34,39°≈0,8252