Question

x•y-3x=14
x=?
y=?

30x+by-26=25
30+8=2c+25
x=?

Answer 1

x*y-3x=14
x*y=14+3x....=>...3x=x*y-14
3x-x+y=14....=>2x+y=14
y=14-2x.......=>y=(14+2*3):2.....=>y=(14+6):2....=>y=20:2...=>y=10
x=2*3:3....=>x=6:3....=>x=2

2*10-2*3=
=20-6
=14

30x+b*y-26=25
30x+b*y=25+26
30x+b*y=51
b*y=51-30x
b*y=21x
x=(25+26-21):30
x=(51-21):30
x=30:30
x=1
21:3=7....=> b=7 si y=3 (sau invers)

30*1+7*3-26=
=30+21-26
=51-26
=25