X-3y=7
-7x+y=-69
x=7+3y
-7(7+3y)+y=-69
-49-21y+y=-69
-20y=-20
y=1
y=1
x=7+3*1
y=1
x=10
<span> куб разности <span><span>(<span>a-b</span>)</span>^3</span> = <span><span><span><span>a^3-</span><span><span>3<span>a^2</span></span>b</span></span>+<span><span>3a</span><span>b^2-</span></span></span><span>b^3</span></span> </span><span>.
(a-1)^3= a^3-3a^2+3a-1</span>
1/5=5⁻¹
(1/5)²⁻³ˣ= 5²
5³ˣ⁻² = 5²
3х-2=2
3х=4
х=4/3
\\\\\\\\\\\\\\\\\\\\\\\\\\