4.
x + y + z = 12
x + y + z = 48
3x – 2y – z = ?
= = = 4
= = 4
4 = 4 => x = y = z = 4
3x – 2y – z = O
6.
x+ 2x– 4x + 1 = 0
x+ x + x – ?
x+ x + x = -2
x+ x+ x+ x + x+ x = -4
( x+ x + x) = x+ x + x + 2 (x+ x+ x+ x + x+ x)
= (-2) = 4
x+ x + x+ 2 (-4) = 4
x+ x + x = 12
7.
2*10
2*5 և 5*2
4*5
2 + C = 2 + = 2 + = 2 + 21 = 23
8.
BC = AB+ AC – 2AB AC * cos A
196 = 100 + 256 – 2*160 * cos A = => A = 60=> անկ․ BEC = 180– 60 = 120=> անկ․ EBC = = 30