Question

(16000+9*(900-50x)*4)/50-80*6=20

Answer 1

(16000+9*(900-50х)*4)/50-80*6=20
((16000+(8100-450х)*4)/50-480=20
(16000+32400-1800х)/50-480=20
16000/50+32400/50-1800х/50-480=20
320+648-36х-480=20
-36х=20-320-648+480
-36х=-468
х=468*36
х=13