`\text {@Luffy Cat}`
`\text {Happy Birthday Hoidap247}`
a,2x + 50 = 49
2x =49 - 50
2x =-1
x =-1 : 2
x =$\frac{-1}{2}$
b,3x + x = 52
4x= 52
x=52 : 4
x=13
c,10x-2x=48
8x=48
x=48 : 8
x=6
d,,x+2x+3x+4x+5x=36
(1+2+3+4+5)x=36
15x=36
x=36:15
x=$\frac{36}{15}$