The side of a square is 3 cm smaller than one of the sides of a rectangle and 2 cm greater than its other side. Find the side of the square, if it’s known that the area of the square is 30 cm2 less than the area of the rectangle.


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[tex]a-the\ side\ of\ square\\a^2-the\ area\ of\ square\\\\a+3-the\ one\ side\ of\ rectangle\\a-2-the\ second\ side\ of\ rectangle\\(a+3)(a-2)-the\ area\ of\ rectangle\\\\\text{The equation:}\\\\(a+3)(a-2)=a^2+30\qquad\text{use distributive property}\\\\(a)(a)+(a)(-2)+(3)(a)+(3)(-2)=a^2+30\\\\a^2-2a+3a-6=a^2+30\qquad\text{subtract}\ a^2\ \text{from both sides}\\\\a-6=30\qquad\text{add 6 to both sides}\\\\\boxed{a=36}\\\\Answer:\ \boxed{36\ cm}[/tex]

By writing and solving a system of equations, we want to find the side of the given square. We will see that the side length of the square is S = 5.52cm

Let's see how to solve the problem:

So we know that the side of the square, S, is 3cm smaller than one side of a rectangle, L, and 2 cm greater than the other side of the rectangle, W.

So we can write this as:

  • S = L - 3cm
  • S = W + 2cm

We also know that the area of the rectangle is 30cm^2, remember that the area is just the product between the measures of both sides, so we have:

L*W = 30cm^2

We can write this as:

L = (30cm^2)/W

And replace it on the first equation to get the system of equations:

  • S = (30cm^2)/W - 3cm
  • S = W + 2cm

So now we have two equations and two variables.

We want to find the value of S, so we can isolate W in one of the equations, if we isolate W in the second one we get:

W = S - 2cm

Now we can replace this on the first equation to get:

S = (30cm^2)/(S - 2cm) - 3cm

Now let's multiply both sides by (S - 2cm)

S*(S - 2cm) = 30cm^2 - 3cm*(S - 2cm)

S^2 - 2cm*S = 30cm^2 - 3cm*S + 6cm^2

Moving all the terms to the same side we get:

S^2 + 1cm*S - 36cm^2 = 0

This is just a quadratic equation, the solutions are given by:

[tex]S = \frac{-1cm \pm \sqrt{(1cm)^2 - 4*1*(-24cm)} }{2} \\\\S = \frac{-1cm \pm 12.04cm}{2}[/tex]

We only care for the positive solution, which is:

S = (-1cm + 12.04cm)/2 = 5.52cm

Concluding, the side length of the square is 5.52cm

If you want to learn more about systems of equations you can read:

https://brainly.com/question/13729904

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