Help me with this pls I dont understand ​

y = 18

a = -2

Step-by-step explanation:

Hello There!

For the first one we need to create an equation to solve for y

23+7=y+12

30=y+12

isolate the variable using inverse operations

subtract 12 from each side

30-12=18

we're left with y = 18

for the second one we need to create an equation to solve for a

3+15+a=8+8+8

3+15=18

8+8+8=16

16=18+a

step 1 subtract each side by 18

16-18=-2

we're left with a = -2

cut 138 centimeters off

step-by-step explanation:

250-112 = 138

d

step-by-step explanation: