tolong dong soal nomor 12

Harga a = 2/3b
5a+3b=1.140.000
10/3b+9/3b =1.140.000
19/3b =1.140.000
b=1.140.000 x 3/19
b=180.000
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4a+2b=8/3b+6/3b
=14/3b
=14/3 x 180.000
=840.000