Հանրահաշիվ․ Ռացիոնալ հավասարումներ

265.
ա. x + y = 3
x = 1
y = 2
1 + 2 = 3

բ. 2x + y = 1
x = 1
y = 2
1 + 2 ≠ 1

գ. 3x + 2y = 7
x = 1
y = 2
3 + 4 = 7

դ. x² + y² = 3
x = 1
y = 2
1² + 4 ≠ 3:

266.
ա. x + y = 5
x = 3
y = 2
3 + 2 = 5

բ. 3x + y = 5
x = 1
y = 2
3 + 2 = 5

գ. 2x – 3y = 1
x = 5
y = 3
10 – 9 = 1

դ. x² + y² = 9:

268.
ա. x + y + z = 10
x = 3
y = 5
z = 2
3 + 5 + 2 = 10

բ. x² + y² + z² = 25
x = 5
y = -5
z = 5
25 + (-25) + 25

գ. xy + yx + zy = 3
xy = 1
yx = 1
zy = 1
1 + 1 + 1 = 3

դ. xy – yx + yz = 1
xy = 1
yx = 1
yz = 1
1 – 1 + 1 = 1:

272.
ա. x + y  = 2
x² – yx + y² = 1
x = 1
y = 1
1 + 1 = 2
1² – 1 • 1 + 1²

բ. xy + x² = 2
2x + 3y = 4
x = 1
y = 1
1 • 1 + 1 = 2
1 • 1 + 1 • 1 • 1 ≠ 4

գ. x² + y² = 10
2x – y = 1
1² + 1² ≠ 10
1 – 1 ≠ 1

դ. 3x + 2y = 5
x + 2xy = 3
x = 1
y = 1
1 • 1 • 1 + 1 • 1 ≠ 5
1 + 1 • 1 ≠ 3:

273.
ա. x + y + z = 3
3x – 2y + z = 0
x² + y² + z² = 1
x = 1
y = 1
z = 1
1 + 1 + 1 = 3
1 – 1 + 1 = 0
1 + 1 + 1 ≠ 1

բ. x + y + z = 3
xy + xz + yz = 3
x² + x – y = 1
x = 1
y = 1
z = 1
1 + 1 + 1 =3
1 • 1 + 1 • 1 + 1 • 1 = 3
1² – 1 – 1 ≠ 1

գ. 2x + 3y + 4z = 8
xy – 3x² + z = -1
x² + y² – z² = 1
x = 1
y = 1
z = 1
1 • 1 + 1 • 1 • 1 + 1 • 1 • 1 • 1 ≠ 8
1 • 1 – 1 • 1 • 1² + 1 ≠ -1
1² + 1² – 1² = 1

դ. x² + y² + z² = 2
x + y + z = 3
xy + yz = 2
x = 1
y = 1
z = 1
1² + 1² + 1² ≠ 2
1 + 1 + 1 = 3
1 • 1 + 1 • 1 = 2:

275.
ա. x + y + z = 3
x – y – z = -2
xy + x² = 2
x = 1
y = -1
z = 1
1 + (-1) + 1 ≠ 3
1 – (-1) – 1 ≠ -2
1 • 1 + 1 = 2

բ. x + y + z = 3
x – y – z = -2
xy + x² = 2
x = 1
y = 1
z = 1
1 + 1 + 1 = 3
1 – 1 – 1 ≠ -2
1 • 1 + 1² = 2

գ. x + y + z = 3
x – y – z = -2
xy + x² = 2
x = 1
y = 1
z = -1
1 + 1 + (-1) ≠ 3
1 – 1 – (-1) ≠ -1
1 • 1 + 1 = 2

դ. x + y + z = 3
x – y – z = -2
xy + x² = 2
x = -1
y = 1
z = 1
-1 + 1 + 1 ≠ 3
-1 – 1 – 1 ≠ -2
-1 • 1 + -1² ≠ 2: