Question

Pada sistem persamaan 2p + 3p = 2 dan 4p -q = 18, nilai 5p - 2q² adalah.....

Answer 1

2p + 3q = 2 dikali 1
4p - q = 18 dikali 3
-----------------------------
2p - 3q = 2
12p -3q = 54
--------------------- +
14p = 56
p = 56 / 14
p = 4

masukkan ke persamaan 1
2p+3q = 2
2(4) + 3q = 2
8 + 3q = 2
3q = 2 - 8
3q = -6
q = -2

nilai 5p - 2q² =
5(4) - 2(-2)²
20 - 2(4)
20-8 = 12

Answer 2

2p + 3q = 2 (kalikan 2)
4p - q = 18 

4p + 6q = 4
4p -  q = 18
__________-
 7q = -14
  q = -2

4p - q = 18
4p - (-2) = 18
4p = 18-2
4p = 16
p = 4

5p - 2q² = 5(4) - 2(-2²) = 20-8 = 12