The length of the rectangle is 3cm more than the width.
1. using x for the width, write down an expression for the length.
2.write down a simplified expression for the area
3. the area of the rectangle is more than 18cm^2 but less than 40cm^2
4. complete the inequality for the area. 18 5.solve the inequality
please anwswer this. thanks :)
1. using x for the width, write down an expression for the length.
2.write down a simplified expression for the area
3. the area of the rectangle is more than 18cm^2 but less than 40cm^2
4. complete the inequality for the area. 18 5.solve the inequality
please anwswer this. thanks :)
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1. l = x + 3 (l is length)
2. A = l * x = (x + 3) * x = x^2 + 3x cm^2
3. 18 < A < 40
4. 18 < x^2 + 3x < 40
5. What values of x satisfy the equation x(x + 3) such that x is greater than 18 and least than 40?
The answer is x = 4. I found this by enumeration of testing x values from 1 to 5 in the equation. That's not the right way to solve a general double inequality.
Try.
18 < x^2 + 3x
0 < x^2 + 3x - 18
(x + 6)(x - 3), x is -6 and 3.
x^2 + 3x < 40
x^2 + 3x - 40 < 0
(x + 8)(x - 5) < 0
x = -8, 5
But we are looking for a value of x that is greater than 18 and less than 40, so take the value in between x = 3 and x = 5 which is x = 4. The negative values aren't considered because you are dealing with length of the sides of a rectangle.
2. A = l * x = (x + 3) * x = x^2 + 3x cm^2
3. 18 < A < 40
4. 18 < x^2 + 3x < 40
5. What values of x satisfy the equation x(x + 3) such that x is greater than 18 and least than 40?
The answer is x = 4. I found this by enumeration of testing x values from 1 to 5 in the equation. That's not the right way to solve a general double inequality.
Try.
18 < x^2 + 3x
0 < x^2 + 3x - 18
(x + 6)(x - 3), x is -6 and 3.
x^2 + 3x < 40
x^2 + 3x - 40 < 0
(x + 8)(x - 5) < 0
x = -8, 5
But we are looking for a value of x that is greater than 18 and less than 40, so take the value in between x = 3 and x = 5 which is x = 4. The negative values aren't considered because you are dealing with length of the sides of a rectangle.