4(x+3)=7x-33
4x+12=7x-33
-3x=-45
x=15
при х=15
<span>
<span>при а = 1/8, у = - 1/6
</span></span>
16 а + 2 у = 16 * <span><span>1/8 </span>+ 2 *(</span><span><span>- 1/6) = </span></span>16<span>/8 - 2</span><span>/6 = </span>2 - 1<span>/3 = </span>1 2/3
У меня так получилось :
1)240/289
2)tg альфа
3)x=±π/2+6πn
5)x=±2π/15+2πn/5
x=±π/15+2πn/5
AB=√(0-2)²+(1-1)²+(6-2)²=√(4+0+16)=√20
BC=√(2-0)²+(5-1)²+(6-6)²=√(4+16+0)=√20
CD=√(0-2)²+(5-5)²+(2-6)²=√(4+0+16)=√20
AD=√(0-2)²+(5-1)²+(2-2)²=√(4+16+0)=√20
AB=BC=CD=AD