Jika a dan b adalah penyelesaian dari sistem persamaan 4a - 3b = 22 dan 3a + 7b =-2 ,maka nilai 2a + 5b adalah?........ Thnks

4a - 3b = 22
4a = 22 + 3b
a = (22 + 3b)/4

3a + 7b = -2
3 ((22 + 3b)/4) + 7b = -2
3/4 (22 + 3b) + 7b = -2
3/4 (22 + 3b) + 4/4 (7b) = -2
3 (22 + 3b) + 4 (7b) = -2 (4)
66 + 9b + 28b = -8
37b = -74
b = -2

maka , a = (22 + 3b)/4 = (22 + 3 (-2)) / 4 = (22 - 6) / 4 = 16 / 4 = 4

2a + 5b = 2 (4) + 5 (-2) = 8 + (-10) = -2

4a - 3b = 22 (x3)
3a + 7b = -2 (x4)

12a - 9b = 66
12a + 28b = -8
_________ -
37b = 74
b = -2
4a - 3b = 22
4a - (3 x -2) = 22
4a + 6 = 22
4a = 22 - 6
4a = 16
a = 4

2a + 5b =
= (2 x 4) + (5 x -2)
= 8 + - 10
= -2

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