The problem describes a trapezium with an area of $15 \text{ cm}^2$. The lengths of the parallel sides are $(x-4)$ cm and $(x+2)$ cm, and the height is $x$ cm. The task is to form a quadratic equation based on the situation.

AlgebraQuadratic EquationsGeometryArea of Trapezium
2025/4/10

1. Problem Description

The problem describes a trapezium with an area of 15 cm215 \text{ cm}^2. The lengths of the parallel sides are (x4)(x-4) cm and (x+2)(x+2) cm, and the height is xx cm. The task is to form a quadratic equation based on the situation.

2. Solution Steps

The area of a trapezium is given by the formula:
Area=12×(sum of parallel sides)×heightArea = \frac{1}{2} \times (sum \ of \ parallel \ sides) \times height
In this case, the area is 15 cm215 \text{ cm}^2, the parallel sides are (x4)(x-4) cm and (x+2)(x+2) cm, and the height is xx cm. Substituting these values into the formula, we get:
15=12×((x4)+(x+2))×x15 = \frac{1}{2} \times ((x-4) + (x+2)) \times x
Simplifying the expression inside the parentheses:
15=12×(2x2)×x15 = \frac{1}{2} \times (2x - 2) \times x
Multiplying both sides by 2:
30=(2x2)×x30 = (2x - 2) \times x
Expanding the right side:
30=2x22x30 = 2x^2 - 2x
Rearranging the equation to form a quadratic equation in the standard form ax2+bx+c=0ax^2 + bx + c = 0:
2x22x30=02x^2 - 2x - 30 = 0
We can divide the equation by 2 to simplify it:
x2x15=0x^2 - x - 15 = 0

3. Final Answer

The quadratic equation that represents the situation is x2x15=0x^2 - x - 15 = 0.

Related problems in "Algebra"

Given an arithmetic sequence $\{a_n\}$ and its sum of the first $n$ terms $S_n$. We are given that $...

Arithmetic SequenceSeriesSummation
2025/4/18

Given an arithmetic sequence $\{a_n\}$, we know that $a_1 + a_7 = 42$. We are asked to find the sum ...

Arithmetic SequencesSeriesSummation
2025/4/18

We are given a geometric sequence ${a_n}$ with the sum of the first $n$ terms denoted as $S_n$. We k...

Sequences and SeriesGeometric SequenceSum of Geometric Series
2025/4/18

We are given an arithmetic sequence $\{a_n\}$ with the sum of the first $n$ terms denoted by $S_n$. ...

Arithmetic SequencesSeriesSummationCommon Difference
2025/4/18

The problem states that ${a_n}$ is a geometric sequence, and $S_n$ represents the sum of the first $...

Sequences and SeriesGeometric SequenceSum of Terms
2025/4/18

Given that the arithmetic mean of $m$ and $2n$ is 4, and the arithmetic mean of $2m$ and $n$ is 5, f...

Linear EquationsSystems of EquationsArithmetic MeanVariables
2025/4/18

We are given an arithmetic sequence $\{a_n\}$ with $a_2 = 6$ and $a_6 = 18$. We need to find the sum...

Arithmetic SequencesSeriesSummation
2025/4/18

We are given a sequence ${a_n}$ such that $a_1 = 1$ and $a_{n+1} = 3a_n + 2$. We need to find the va...

Sequences and SeriesRecursive Sequences
2025/4/18

Solve the equation $3^{2x} - 30 = 3^x$.

Exponential EquationsQuadratic EquationsLogarithmsChange of Base
2025/4/18

The problem is to solve the system of two equations: $b = -a$ $-12 = -6a$ for the variables $a$ and ...

Linear EquationsSystem of EquationsSolving Equations
2025/4/17