數學中的等於

0.3x4200x(90-T)=0.075x1700x(T-20)
1260 x (90-T)=127.5 x (T-20)
1260 x 90-1260 T=127.5 T-127.5 x 20
113400 - 1260 T =127.5 T -2500
113400 + 2500 = 127.5 T+1260 T
115900=1387.5 T
T = 115900 / 1387.5
T = 83.5315315 or 83.53 ( 2 d.p.)

does the "x" stand for "times"?
if it is, then this should be right.

0.3 x 4200 x (90 - T) = 0.075 x 1700 x (T - 20)
1260 x (90 - T) = 127.5 x (T - 20)
113400 - 1260T = 127.5T - 2550
113400 - 1260T + 1260T = 127.5T - 2550 + 2550
113400 + 2550 = 127.5T + 1260T
115950 = 1387.5T
T = 1159500/13875
T = 3092/37

Hope I helped. =]

0.3x4200x(90-T)=0.075x1700x(T-20)
1260x(90-T)=127.5x(T-20)
113400-1260T=127.5T-2550
115950=1378.5T
T=84.1(3.sig.fig)



是否物理數?(混合物)