Question

MATEMATIKA SMA dan BERIKAN PENJELASANNYA​

Answer 1

4a + b = 7

b = 7 - 4a

2a + 3b = 11

2a + 3(7 - 4a) = 11

2a + 21 - 12a = 11

-10a = -10

a = 1

b = 7 - 4a

b = 7 - 4(1)

b = 3

4c + d = 4

d = 4 - 4c

2c + 3d = -8

2c + 3(4 - 4c) = -8

2c + 12 - 12c = -8

-10c = -20

c = 2

d = 4 - 4c

d = 4 - 4(2)

d = -4

Sehingga a + b + c + d

= 1 + 3 + 2 + (-4)

= 2

Jawabannya C