Instead of doing your problem for you, I will do one exactly in every detail
like yours and you can use it as a model to do yours by. I will do this
one instead:
Rectangle of perimeter 38 cm. if its length decreases 2 cm & its width increases
5 cm it will be square. find area of square.
>>Rectangle of perimeter 38 cm<<
P = 2L + 2W
So we substitute 38 for P
38 = 2L + 2W <-- that's one equation
>>if its length decreases 2 cm<<
Then its new length will be L-2
>>& its width increases 5 cm<<
Then its new width will be W+5
>>it will be square<<
Then its length and width will be equal, so
L-2 = W+5 <-- That's another equation.
So we have this system of two equations and 2 unknowns to solve
by substitution:
We can simplify the first equation,
38 = 2L + 2W
by dividing it through by 2, getting,
19 = L + W
We can simplify the second equation,
L - 2 = W + 5
by adding 2 to both sides:
L = W + 7
Now the system is
Since the second equation is already solved for L, we
substitute (W + 7) for L in the first equation, and get:
19 = (W + 7) + W
Remove the parentheses:
19 = W + 7 + W
Combine like terms on the right
19 = 2W + 7
Subtract 7 from both sides
12 = 2W
Divide both sides by 2
6 = W
Substitute 6 for W in
L = W + 7
L = 6 + 7
L = 13
So the original length was 13 cm and the original width 6 cm
>>find area of square<<
So the new length will be L-2 or 13-2 = 11 cm
And its new width will be W+5 or 6+5 = 11 cm
So a side of the square will be 11 cm
So its area will be
A = (side)2 = 112 = 121 square centimeters.
Now do yours which is done exactly the same way, step by step.
Edwin