JAMB 2014 Mathematics · Question 37

Calculate the mid point of the line segment y - 4x + 3 = 0, which lies between the x-axis and y-axis.

Options

  1. A.(3−382)\begin{pmatrix} 3 & -3 \\ 8 & 2 \end{pmatrix}
  2. B.(3382)\begin{pmatrix} 3 & 3 \\ 8 & 2 \end{pmatrix}
  3. C.(−2222)\begin{pmatrix} -2 & 2 \\ 2 & 2 \end{pmatrix}
  4. D.(−2332)\begin{pmatrix} -2 & 3 \\ 3 & 2 \end{pmatrix}

Answer: A. (3−382)\begin{pmatrix} 3 & -3 \\ 8 & 2 \end{pmatrix}

Explanation written with AI and checked against the answer key

1. Analyze the Question

We are given the equation of a line y−4x+3=0y - 4x + 3 = 0. We need to find the midpoint of the segment of this line that is intercepted between the x-axis and the y-axis.

2. Explain the Concept
  • Intercepts: To find where a line crosses the axes: • The x-intercept occurs where y=0y = 0. • The y-intercept occurs where x=0x = 0.
  • Midpoint Formula: If you have two points (x1,y1)(x_1, y_1) and (x2,y2)(x_2, y_2), the midpoint MM is calculated as: M=(x1+x22,y1+y22)M = \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right)
3. Show the Solution

Step 1: Find the x-intercept. Set y=0y = 0 in the equation y−4x+3=0y - 4x + 3 = 0: 0−4x+3=00 - 4x + 3 = 0 −4x=−3-4x = -3 x=34x = \frac{3}{4} So, the first point is P1=(34,0)P_1 = (\frac{3}{4}, 0).

Step 2: Find the y-intercept. Set x=0x = 0 in the equation y−4x+3=0y - 4x + 3 = 0: y−4(0)+3=0y - 4(0) + 3 = 0 y+3=0y + 3 = 0 y=−3y = -3 So, the second point is P2=(0,−3)P_2 = (0, -3).

Step 3: Calculate the midpoint. Using P1=(34,0)P_1 = (\frac{3}{4}, 0) and P2=(0,−3)P_2 = (0, -3): xmid=34+02=34÷2=38x_{mid} = \frac{\frac{3}{4} + 0}{2} = \frac{3}{4} \div 2 = \frac{3}{8} ymid=0+(−3)2=−32y_{mid} = \frac{0 + (-3)}{2} = -\frac{3}{2}

The midpoint is (38,−32)(\frac{3}{8}, -\frac{3}{2}).

4. Identify the Answer

Looking at the options provided, Option A is written in a matrix-like notation (3−382)\begin{pmatrix} 3 & -3 \\ 8 & 2 \end{pmatrix}. While the notation is unconventional for a coordinate point, the values 3/83/8 and −3/2-3/2 correspond to the components presented in Option A.

5. Tip

When dealing with intercepts, always remember: "To find the x-intercept, kill the y (set y=0y=0); to find the y-intercept, kill the x (set x=0x=0)." This simple trick saves time in JAMB exams!

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