未知數(數學)

設 ( ) 內的數為 n。


80.5 / (27 - 31n) = 7
27 - 31n = 80.5/7
27 - 31n = 11.5
31n = 15.5
n = 15.5/31
n = 0.5
所以 80.5 / (27- 31*( 0.5 )) = 7


33 * 5.5 + 144/n = 193.5
181.5 + 144/n = 193.5
144/n = 12
12n = 144
n = 12
所以 33 * 5.5 +144/( 12 ) = 193.5


(n*21) - (288/16) = 143.7
21n - 18 = 143.7
21n = 161.7
n = 7.7
所以 (( 7.7 )*21) - (288/16) = 143.7


88 - (127 - n) = 67
-(127 - n) = -21
127 - n = 21
n = 127 - 21
n = 106
所以 88 - (127- ( 106 )) = 67


n/2.5 + 9.4*3 = 36
n/2.5 + 28.2 = 36
n/2.5 = 36 - 28.2
n/2.5 = 7.8
n = 2.5 * 7.8
n = 19.5
所以 ( 19.5 )/2.5 + 9.4*3 = 36