I am unsure about the very last problem but I can help with the first two
1) (y+1)+4
If we combine the numbers 1 and 4, we get +5 and can isolate the numbers from the variable.
This would give us

2) (6*r)*7
remember that we do not have to explicitly state 6*r
Instead, we can write it as 6r
this helps us get rid of the parentheses
now we can write it as

I hope this helps!:)
Answer:
$8.00
Step-by-step explanation:
Let's set up the equation first.
What do we know:
1. We have 6 friends spliting the costs of the gifts
2. After purchasing the gifts they have $42 in change
3. They originally had $90 to spend.
Equation:
6f + $42 = $90
Next: Subtract the $42 from each side and we are left with:
6f = $48
Divide both sides by 6 and we are left with
f = $8
Since f represented the cost each friend spent our answer is $8.00
Answer:
15393.8cm sorry if im wrong
Answer: Yes
Step-by-step explanation: The answer of 1400 is correct.
What I did is I found the area of the figure assuming it was a rectangle, then I subtracted the corners that were removed.
1800 - 150 - 100 - 150 = 1400