А×948=429690+6390
а×948=436080
а=436080÷948
а=460
273996/b=16151-15764
273996/b=387
b=273996÷387
b=708
(50-x)/7=200-195
(50-x)/7=5
50-x=5×7
50-x=35
x=50-35
x=15
270/y-2=840÷30
270/y-2=28
270/y=28+2
270/y=30
y=270÷30
y=9
Sin2a=√2sina
2sinacosa-√2sina=0
sina(2cosa-√2)=0
sina=0⇒a=πn,n∈z
cosa=√2/2
a=+-π/4+2πk,k∈z