To answer this kind of question, you need to insert the first equation into second equation or vice versa. The equation from the question should be:
1. 3 paperback books + 5 hardcover book = $80.10
2. 7 paperback books + 4 hardcover book= $100.65
It would be easier to convert the 1st equation into
5 hardcover book = $80.10- 3 paperback books
hardcover book= $16.02- 0.6 paperback books
Then insert it to 2nd equation:
7 paperback books + 4 ($16.02- 0.6 paperback books)= $100.65
7 paperback books + $64.08- 2.4 paperback books= $100.65
4.6 paperback books = $100.65- $64.08= $36.57
paperback book= $7.95
Insert paperback book price to the first equation to find the hardcover book price
3 paperback books + 5 hardcover book = $80.10
3 ($7.95)+ 5 hardcover book = $80.10
5 hardcover book = $80.10 - $23.85= $56.25
hardcover book = $11.25
Then one paperback and one hardcoverbook= $7.95 + $11.25= $19.20
1 is : d>-9
2 is: k ≥ -18
3 is: g>-1
4 is: n<-40
5 is: w ≤3
That should be correct.
It would be x+3y=15. Best of luck
Let x be the width of the playground, then 3x is the length of the
<span>playground
х * 3х = 75
3x</span>² = 75
x² = 25
x = 5 m (width)
5*3=15 m (length)
Perimeter = 2(5+15) = 2*20 = 40 meters.
