Looks like you did most of it.
The next step would be setting them equal to 105, like the problem suggests.



Then we can plug back in to find the numbers.




The three numbers are
.
Hope this helps.
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Answer:
The linear equation is;
Y = 450 - 2·X
Please find the included graph
Step-by-step explanation:
Whereby we have the following relation;
The cost of 1 pizza = X
The cost of 1 burger = Y
Hence;
450 = Y + 2·X
Which gives;
Y = 450 - 2·X
The linear equation for the situation is therefore as presented above
The graph of the linear equation can be plotted using the assumed data as follows;
Y, X
1, 448
2, 446
3, 444
4, 442
5, 440
6, 438
7, 436
8, 434
9, 432
10, 430
11, 428
12, 426
13, 424
14, 422
15, 420
16, 418
You can use a number line to add and subtract
A = l x w
so you know that the length is 3m longer than the width, so you could use a formula to represent that
w = l + 3
you then substitute the second equation into the first to solve for l
70 = l x (l +3)
70 = l^2 + 3l
you could then rearrange the formula and solve for l using the quadratic formula
0 = l^2 + 3l - 70
l = -3 +- (square root (3)^2 - 4(1)(70)) / 2(1)
l = -3 +- (square root 9 + 280) / 2
l = -3 +- (square root 289) / 2
l = -3 +- 17 / 2
then you solve for the two seperate roots
l = -3 + 17 /2
l = 14 / 2
l = 7
or
l = -3 - 17 / 2
l = -20 / 2
l = -10
since a length cannot be negative, this root is not viable. therefore l = 7
to solve for w you would use
w = l + 3
w = 7 + 3
w = 10
hope this helps! if you did not understand a step or concept please let me know!