CLASS_11_MATHS_SOLUTIONS_NCERT

Class XI Chapter 10 – Straight Lines Maths
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Question 4:
Find a point on the x-axis, which is equidistant from the points (7, 6) and (3, 4).
Solution 4:
Let (a, 0) be the point on the X- axis that is equidistance from the points (7, 6) and (3, 4).
2 2
2 2
Accordingly, 7a 6 0
= 3a 4
0
2 2
49 a 14a 36 9 a 6a
16
2 2
a 14a 85 a 6a
25
On squaring both sides, we obtain
2 2
a 14a 85 a 6a
25
14a 6a 25 85
8a
60
60 15
a
8 2
15
Thus, the required point on the x-axis is ,0
2
Question 5:
Find the slope of a line, which passes through the origin, and the mid-point of the segment
joining the points P (0, -4) and B (8, 0).
Solution 5:
The coordinates of the mid-point of the line segment joining the points
08 4 0
P (0, -4) and B (8, 0) are , (4, 2)
2 2
It is known that the slope (m) of a non-vertical line passing through the points (x1, y1) and (x2,
y2
y1
y2) is given by m , x2 x1
x x
2 1
Therefore, the slope of the line passing through (0, 0,) and (4, -2) is
Hence, the required slope of the line is
1
.
2
2 0 2 1
40 4 2
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