Răspuns :
7a + 9b + 5 = a + b + 17
6a + 8b = 17 - 5 = 12
2(3a + 4b) = 12
3a + 4b = 6
15a + 20b = 5(3a + 4b) = 5 x 6 = 30
15a + 20b = 3
6a + 8b = 17 - 5 = 12
2(3a + 4b) = 12
3a + 4b = 6
15a + 20b = 5(3a + 4b) = 5 x 6 = 30
15a + 20b = 3
7a+9b+5=a+b+17
6a+8b=17-5
6a+8b=12 /:2
3a+4b=6
12×ab=6
ab=2
15a+20b=>
(15+20)×2=35×2=70
6a+8b=17-5
6a+8b=12 /:2
3a+4b=6
12×ab=6
ab=2
15a+20b=>
(15+20)×2=35×2=70