Решите уравнения: 1) 7\9 = 351 \ x + 400; 2) 3\11 = x + 140 \ 517; 3) 444 \ x -480 = - 12...

1) $\frac{7}{9} = \frac{315}{x+400}$
7(х+400)=9*315
7х+2800=2835
7х=2835-2800
х=35/7=5

2) $\frac{3}{11} = \frac{x+140}{517}$
11(х+140)=3*517
11х+1540=1551
11х=1551-1540=11
х=11/11=1

3) $\frac{444}{x-480}=- \frac{12}{13}$
-12(х-480)=13*444
-12х+5760=5772
-12х=5772-5760=12
х=12/-12=-1