1.8(x+8)-4=2x+2
1.8x+ 14.4-4=2x+2
1.8x+ 10.4=2x+2
2x- 1.8x= 10.4-2
0.2x=8.4
x=42
42 yuan for mutton and (x+8) for beef x+8)= 50 yuan.