<span>1) a(x-y)+4(x-y) = </span><span>(x-y)(а+4)
2) 3x-3y+ax-ay</span> = <span>3(x-y) + a(x-y</span>) = (x-y)(<span>3+a</span>)
<span><span>1-sin2</span><span>=cos2</span><span>
ctg2</span><span>*sin2</span><span>=cos2</span><span>
cos2</span><span>+cos2</span>=2cos2</span>
n)
<span><span>sin2</span>+<span><span>cos2</span></span>=1</span>
Баллов даешь мало, а хочешь много)) номер 3, 100% верно решила
Sin(π/6-a)=cos(π/3+a)
cos(π/3+a)-cos(π/3+a)=0