А) 63+(78-х)•5=363 б) (54•х+2760)=42

А) 63 + (390 - 5x) = 363
63 + 390 - 5x = 363
-5x = 363 - 390 - 63
-5x = - 90
5x = 90
x = 90/5 = 18
б) 54x + 2760 = 42
54x = 42 - 2760
54x = −2718
x = −2718/54 = −50,(3)