Question

1000-[5+2X(100+yX4)-124:4]=754

Answer 1

1000-[5+2x(100+yx4) - 31]=754 
5+2x(100+yx4) -31= 1000-754
5+2x(100+yx4)-31=246
5+2x(100+4xy)=246+31
5+2x(100+4xy)= 277
2x(100+4xy) = 277 -5
2x(100+4xy)=272
100+4xy= 272:2
100 +4xy= 136
4xy= 136-100
4xy=36
y=36:4
y= 9

Answer 2

1000-(5+2(100+4y)-31)=754
1000-(5+200+8y-31)=754
1000-(174+8y)=754
1000-174-8y=754
826-8y=754
-8y=754-826
-8=-72
y=9