√15*√12/√20 (упрощаем выражение)
√15*√3/√5 (сокращаем 15 и 5)
√3√3
3
3*x*y-8 = 3*x^3 / y*2*x*y+48 , 3*x^3 / y*2*x*y+48 = 2*y^3 / x
<span>a=(2;3) b=(1;8) c=(4;2)</span>
<span>1) a+b=(2+1;3+8)=(3;11)</span>
<span> Ia+bI=sqrt(3^2+11^2)=sqrt130</span>
<span>2) 2a-b=(2*2-1;2*3-8)=(3;-2)</span>
<span> I2a-bI=sqrt(3^2+(-2)^2)=sqrt13</span>
<span>3) a+2b-3c=(2+2-12;3+16-6)=(-8;13)</span>
<span> Ia+2b-3cI=sqrt(64+169)=sqrt233</span>
<span>4) 4a=(8;12)</span>
<span> I4aI=sqrt(64+144)=sqrt208</span>
<span>5) 3a-8b=(-2;-55)</span>
<span> I3a-8bI=sqrt(4+3025)=sqrt3029</span>
А1=-2•1+3=1
а2=-2•2+3=–1
d=a2–a1=–1–1=–2
a60=-2•60+3=–117
S60=(a1+a60)/2•60=(1–117)/2•60 =
= –3480
5b²/(a-7b)(a+7b) *a(a+7b)/b=5ab/(a-7b)