How do you know when to use the addition property of a equality?

Avery’s piggy bank has 300 nickels, 450 pennies, and 150 dimes. she randomly picks three coins. each time she picks a coin, she makes a note of it and puts it back into the piggy bank before picking the next coin.

Huong is organizing paperback and hardback books for her club's used book sale. the number of paperbacks is 12 less than three times the number of hardbacks. huong had 162 paperbacks. how many hardback books were there?

(2, 4) (2, 1) (6, 12) (4, -5) (-2, 4) |(2, -4) (6, -12) (-4,5) quadrilateral abcd is reflected over the x-axis. quadrilateral abcd is translated 2 units right and 1 unit down. quadrilateral abcd is dilated by a scale factor of 3. quadrilateral abcd is rotated 180° clockwise about the origin. reset next