a){720:[41-(7.2\(^2\)- X)] }:(2\(^3\).5)=1
{720:[41-(7.4-X)] }:(8.5)=1
{720:[41-(28-X)] }:40=1
41-(28-X):40=1.720
41-(28-X):40=720
(28-X):40=720+41
(28-X):40=716
28-X =716.40
28-X=28640
X=28-28640
X=(-28612)
b)420+65.4=(x+175):5+30
420+260=(x+175):5+30
280=(x+175):5+30
(x+175):5=280-30
(x+175):5=250
x+175=250.5
x+175=1250
x=1250-175
x=1075
c)(32.15):2=(x+70):14-40
480:2=(x+70):14-40
240=(x+70):14-40
(x+70):14=240+40
(x+70):14=280
x+70=280.14
x+70=3920
x=3920-70
x=3850