∵x-42与25互为倒数,
∴x-42×25=1,
解得:x=9.
故填9.
The old scientist has made a great contribution the moon.
A.in explore
B.to explore
C.explore
D.to exploring
当所受外力与材料内轴线垂直,并在作用后使材料呈弯曲时表现出来的抵抗能力叫抗变强度。