Question

4x + 3y = 23 , 5x - 7y = -25 nilai -3x + 6y =

Answer 1

4x + 3y = 23 | x5 | 20x + 15y = 115
5x - 7y = -25 | x4 | 20x - 28y = -100 -
                                   43 y = 215
                                        y = 215/53 = 5

4x + 3y = 23
4x + 3(5) = 23
4x + 15 = 23
4x = 23 - 15
4x = 8
x = 8/4
x = 2

Nilai -3x + 6y :
-3(2) + 6(5)
= -6 + 30
= 24

Answer 2

4x + 3y = 23 | x5 | 20x + 15y = 115
5x - 7y = -25 | x4 | 20x - 28y = -100
                           ------------------------  --
                                       43y = 215
                                           y = 5

subtitusikan ke 4x + 3y = 23

4x + 3(5) = 23
4x + 15 = 23
4x = 23 - 15
4x = 8
x = 8/4
x = 2

-3x + 6y
-3(2) + 6(5)
-6 + 30
24