Odpowiedź:
1.
1000a + 100b + c = 1000 * 2 + 100 * 7 + 3 = 2000 + 700 + 3 = 2703
dla a = 2, b = 7, c = 3
odp. C.
2.
2x - (x² - 5) = 2(-2) - (4 - 5) = -4 - (-1) = -4 + 1 = -3
dla x = -2
odp. B.
3.
x = 5
y = 1/2
?x ≠ 10
A.
1/2(5x - 10y) = 1/2(5*5 - 10*1/2) = 1/2(25 - 5) = 1/2 * 20 = 10 nie
B.
2x - 2y + 1 = 2 * 5 - 2 * 1/2 + 1 = 10 - 1 + 1 = 10 nie
C.
1/2x + 15y - 5 = 1/2 * 5 + 15 * 1/2 - 5 = 2 1/2 + 7 1/2 - 5 = 10 - 5 = 5 TAK
D.
4/9(x - y)² + 1 = 4/9(5 - 1/2)² + 1 = 4/9(4 1/2)² + 1 = 4/9 * (9/2)² + 1 = 4/9 * 81/4 + 1 = 9 + 1 = 10
Szczegółowe wyjaśnienie:
