How does using a jack make changing a tire easier

when using a jack it lifts up the car for you, giving you the ability to remove and replace a tire without the weight of the car on the tire.

i think it's c. i'm not sure but i think so.

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer