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The sum of the perimeter of the rectangles is 40cm. The sum of their area is 46 cm^2. Find the values of x and y.

Could you explain how to do the calculation?

The sum of the perimeter of the rectangles is 40cm The sum of their area is 46 cm2 Find the values of x and yCould you explain how to do the calculation class=

Respuesta :

  • Perimeter of a rectangle = [tex] 2b+2h [/tex]
  • Area of a rectangle = [tex] bh [/tex]

So for this, we will be doing a system of equations, one representing the sum of their areas and the other representing the sum of their perimeters:

[tex] 2x+9y=46\\\\4+2x+18+2y=40\\2x+2y+22=40 [/tex]

So with this, I will be using the elimination method. So firstly, subtract 22 on both sides of the second equation:

[tex] 2x+9y=46\\2x+2y=18 [/tex]

Next, subtract the second equation from the first equation and you should get [tex] 7y=28 [/tex] . From here we can solve for y.

For this, just divide both sides by 7 and your first answer will be y = 4.

Now that we have the value of y, substitute it into either equation to solve for x as such:

[tex] 2x+9*4=46\\2x+36=46\\2x=10\\x=5\\\\2x+2*4=18\\2x+8=18\\2x=10\\x=5 [/tex]

In short, x = 5 and y = 4.