x - 3 = 55
x = 55 + 3
x = 58
r + r + 3 x 5 = 85
r x 2 + 3x 5 = 85
r x 2 + 15 = 85
r x 2 = 85 - 15
r x 2 = 70
r = 70 : 2
r = 35
a)X=55-3=52
b)=r*2+3*5=85
(r*2+3) =85/5
(r*2+3) =17
(r*2) =17-3
(r*2) =14
r =14/2
r =7 nha
x-3=55
x=55+3
x=58
r+r+3x5=85
2r+3x5=85
2r+15=85
2r=85-15
2r=60
r=60:2
r=30
a) x-3=55
x=55+3
x= 58
b) r+r+3x5=85
rx2+ 15 =85
rx2 =85-15
rx2 = 70
r = 70 : 2
r = 35