1. **Problem statement:** Given points P(-3,4), M(a,2) which is the midpoint of PQ, and Q lies on the x-axis (so Q's y-coordinate is 0). We need to find:
2.1 The gradient of PQ.
2.2 The equation of the perpendicular bisector of PQ.
2.3 The coordinates of Q using the midpoint formula.
2.4 The length of PM to two decimal places.
2.5 The equation of the line parallel to the y-axis passing through P.
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2.1 **Gradient of PQ:**
The gradient formula is $$m = \frac{y_2 - y_1}{x_2 - x_1}$$ where $P(x_1,y_1)$ and $Q(x_2,y_2)$.
Since Q lies on the x-axis, $Q = (x_Q, 0)$.
So, $$m_{PQ} = \frac{0 - 4}{x_Q - (-3)} = \frac{-4}{x_Q + 3}$$.
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2.2 **Equation of the perpendicular bisector of PQ:**
The perpendicular bisector passes through midpoint M and has slope the negative reciprocal of $m_{PQ}$.
Slope of perpendicular bisector:
$$m_{perp} = -\frac{1}{m_{PQ}} = -\frac{1}{\frac{-4}{x_Q + 3}} = \frac{x_Q + 3}{4}$$.
Equation using point-slope form:
$$y - 2 = m_{perp}(x - a)$$.
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2.3 **Coordinates of Q using midpoint formula:**
Midpoint formula:
$$M = \left(\frac{x_P + x_Q}{2}, \frac{y_P + y_Q}{2}\right)$$.
Given $M = (a, 2)$, $P = (-3,4)$, and $Q = (x_Q, 0)$:
$$a = \frac{-3 + x_Q}{2}$$
$$2 = \frac{4 + 0}{2} = 2$$ (confirms midpoint y-coordinate)
From the first equation:
$$2a = -3 + x_Q \Rightarrow x_Q = 2a + 3$$.
So, $Q = (2a + 3, 0)$.
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2.4 **Length of PM:**
Distance formula:
$$PM = \sqrt{(x_M - x_P)^2 + (y_M - y_P)^2}$$
Substitute $P(-3,4)$ and $M(a,2)$:
$$PM = \sqrt{(a + 3)^2 + (2 - 4)^2} = \sqrt{(a + 3)^2 + (-2)^2} = \sqrt{(a + 3)^2 + 4}$$.
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2.5 **Equation of line parallel to y-axis through P:**
Lines parallel to the y-axis have equations of the form:
$$x = k$$
Since it passes through $P(-3,4)$, the equation is:
$$x = -3$$.
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**Summary:**
- Gradient of PQ: $$m_{PQ} = \frac{-4}{x_Q + 3}$$ with $x_Q = 2a + 3$.
- Perpendicular bisector: $$y - 2 = \frac{x_Q + 3}{4}(x - a)$$.
- Coordinates of Q: $$Q = (2a + 3, 0)$$.
- Length of PM: $$PM = \sqrt{(a + 3)^2 + 4}$$.
- Equation of line parallel to y-axis through P: $$x = -3$$.
Triangle Opq
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