The length of the rectangle is 2 m longer than its width. If the width is increased by 3 m
The length of the rectangle is 2 m longer than its width. If the width is increased by 3 m and the length by 8 m, then the area will increase by 3 times. Find the sides of the rectangle .
1) Let x m be the width of the rectangle (x> 0), then (x + 2) m is its length.
2) (x * (x + 2)) = (x ^ 2 + 2x) m ^ 2 is the area of the rectangle.
3) (x + 3) m – the width of the rectangle after the enlargement, ((x + 2) + 8) = (x + 10) m – the length of the enlarged rectangle.
4) (x + 3) (x + 10) = (x ^ 2 + 13x + 30) m – the area of the enlarged rectangle.
5) From the condition, you can write:
(x ^ 2 + 13x + 30): (x ^ 2 + 2x) = 3.
6) Solve the equation:
x ^ 2 + 13x + 30 = 3 * (x ^ 2 + 2x);
x ^ 2 + 13x + 30 = 3x ^ 2 + 6x;
2x ^ 2 – 7x – 30 = 0.
D = 49 + 240 = 289;
x1 = -2.5, x2 = 6.
7) x1 <0, which means it is not a solution to the problem.
8) x = 6 m – the width of the rectangle.
9) 6 + 2 = 8 m – its length.
Answer: 8 and 6 m.