Question

(a+109)*30=6510

d-(240*13)=1260

Answer 1

(a+109)*30=6510
а+109=6510/30

а+109=217

а=217-109

а=108

проверка:

(108+109)*30=6510

217*30=6510

6510=6510
d-(240*13)=1260

d- 3120=1260

d=1260+3120

d=4380

проверка:

4380-(240*13)=1260

4380- 3120=1260

1260=1260 

Answer 2

1. (a+109)*30=6510

a+109=6510:30

a+109=217

a=217-109

a=108

2. d-(240*13)=1260

d-1260=240*13

d-1260=3120

d=1260+3120

d=4380