Откройте скобки, употреби в Past Simple или Past Perfect 1. They (not see) their nephew for years when - id1814172120220822 от ковязин14 22.08.2022 20:51

Question

Математика: Откройте скобки, употреби в Past Simple или Past Perfect 1. They (not see) their nephew for years when he suddenly (call) from Italy. 2. The meeting already (begin) when they (come) into the hall. 3. After Mike (finish) the painting, he (meet) Paula for dinner. 4. Eva (write) many books before she (win) the prize. 5. Jake (be) round the world and (visit) many countries, but he (not know) the way to the theatre in his hometown. 6. I just (finish) writing the letter when the doorbell (ring). 7. The

ковязин14 · Accepted Answer

X² - 6yz + 2y² = 1
3y² - 4xy +9z² = -1   ⇒
x² -6yz+2y² +3y²-4xy+9z²=0
x²-4xy +4y² +y²-6yz+9z²=0
(x -2y)² + (y - 3z)² = 0   ⇒
x-2y=0
y-3z=0 ⇒
y=3z ; x=2y=6z ⇒ (6z)² - 6·(3z)·z + 2·(3z)² =1 ⇒
(6z)² - 18z² +18z² = 1 ⇒
(6z)² = 1 ⇒ 6z = +/-1
a) z = -1/6   ⇒   y = -1/2 ; x = -1
b) z = 1/6 ⇒ y = 1/2 ; x = 1
ответ: (-1; -1/2; -1/6) ; (1; 1/2 ; 1/6)

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