Math questions

[匿名]

2011-08-05 3:41 am

please to solve the following questions:

1. If the straight line passing through A(a, -5) and B(-3, 3) is parallel
to another straight line of slope 2, find the value of a.

2.If the straight line passing through A(-2. b) and B(-4,-1) is perpendicular to
another straight line passing through C(2,5) and D(-1, 3) m find the value
of b.

3. If M(-1,4) is the mid-point of the line segment joining P and Q(-5, 2), find the
coordinates of P.

4. It is given that A(-2,3), B(4,-5) and C(12,1) are the vertices of a trangle.
a. Find the lengths of AB, BC and AC.
[Leave your answers in surd form if necessary.]
b. Is ABC a right-angled isosceles triangle? Explain your answer.

回答 (1)

魔龍帝齊格益力多

2011-08-05 4:36 am

✔ 最佳答案

If the straight line passing through A(a, -5) and B(-3, 3) is parallel
to another straight line of slope 2, find the value of a.
(-5-3)/(a-3)=2
a=-1
______________________
If the straight line passing through A(-2. b) and B(-4,-1) is perpendicular to
another straight line passing through C(2,5) and D(-1, 3) m find the value
of b.
(5-3)/(2-(-1))*(b-1)/(-2-(-4))=-1
b=-2
___________________
If M(-1,4) is the mid-point of the line segment joining P and Q(-5, 2), find the
coordinates of P(x,y):
(x+(-5))/2=-1
x=3
(y+2)/2=4
y=6
___________________________
AB=10,BC=10,AC=10sqrt2

Slope of AB:=-4/3
Slope of BC=3/4
Mab*Mbc=-1

ABC is
a right-angled isosceles triangle(since AB=BC andAB is perpendicular to BC)

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