Answer:
26. 14 sq.units
27. I think it's near to be 30
28. I think it is the first one
9514 1404 393
Answer:
1 < 15 -2a < 7
Step-by-step explanation:
There are a couple of ways you can do this.
1) Put the minimum and maximum values of a into the expression to see what its corresponding values are:
15-2a for a=4:
15-2(4) = 7
15-2a for a=7:
15-2(7) = 1
Then ...
1 < 15-2a < 7
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2) Solve for a in terms of the value of 15-2a, then impose the limits on a.
x = 15 -2a
2a = 15 -x
a = (15 -x)/2
Now, impose the given limits:
4 < (15 -x)/2 < 7
8 < 15 -x < 14 . . . multiply by 2
-7 < -x < -1 . . . . . . subtract 15
7 > x > 1 . . . . . . . . multiply by -1
1 < 15-2a < 7 . . . . . use x=15-2a
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The vertical extent of the attached graph is the range of possible values of 15-2a. It goes from 1 to 7.
Answer:
1.
Step-by-step explanation:

Let the two numbers be x and y where x is greater than y.
So;
x + y = 3.1 ... (i)
2x - 3y = 7 ... (ii)
This forms a set of simultaneous equations (i) and (ii)
Solving the simultaneous equations by elimination;
We multiply (i) by 2 and (ii) by 1 to get:
2x + 2y = 6.2 ... (i)
2x - 3y = 7 ... (ii)
Subtracting (i) - (ii) we get;
5y = -0.8
y = -0.8/5 = -0.16
x = 3.1 - -0.16 = 3.26
The numbers are 3.26 and -0.16.