1.

The ratio in which (-6,5) divide the join of (-3,-1) and (-8,9) is?

Answer»

\large{\underline{\bf{\red{Given:-}}}}

  • ✦ (-6 ,5) divides the line SEGMENT joining (-3,-1) and (-8,9)

\large{\underline{\bf{\red{To\:Find:-}}}}

  • ratio in which (-6,5) divides the line segment.

\huge{\underline{\bf{\green{Solution:-}}}}

Let the ratio be K:1

Let coordinates of p are (-6,5)

By section formula :-

\bf\purple{(x,y) = ( \frac{mx_2 + nx_1}{m + <klux>N</klux>}, \frac{my_2 + my_1}{m + n}  )}\\

Let m = k and n = 1

The coordinates of p are

\mapsto  \rm\:p( \frac{k \times  - 8 + 1 \times  - 3}{k + 1}, \frac{k \times 9 + 1 \times  - 1}{k + 1}  )\: \\  \\ \mapsto  \rm\:p( \frac{ - 8k - 3}{k + 1}, \frac{9k - 1}{k + 1}) \\  \\   \rm\:it \: is \: given \: that \:  \: p( - 6,5) \\ so  \\  \\ \mapsto  \rm\small\frac{ - 8k - 3}{k + 1}  =  - 6 \:  \: and \:  \:  \frac{9k - 1}{k + 1} = 5  \\  \\   \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \: \underbrace{ \bf\:case \: 1st} \\  \\ \mapsto  \rm\: \frac{ - 8k - 3}{k + 1} =  - 6 \\  \\ \mapsto  \rm\: - 8k - 3 =  - 6(k + 1) \\  \\  \mapsto  \rm\: - 8k - 3 =  - 6k - 6 \\  \\ \mapsto  \rm\: - 3 + 6 =  - 6k + 8k \\  \\\mapsto  \rm\:3 = 2k \\  \\\mapsto  \bf \blue{\:k =  \frac{3}{2} } \\  \\  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \: \underbrace  {\bf\:2nd \: \:  case} \\  \\ \mapsto  \rm\: \frac{9k - 1}{k + 1}    = 5 \\  \\ \mapsto  \rm\:9k - 1 = 5(k + 1) \\  \\\mapsto  \rm\:9k - 1 = 5k + 5 \\  \\\mapsto  \rm\:9k - 5k = 5 + 1 \\  \\  \mapsto  \rm\:4k = 6 \\  \\\mapsto  \rm\:k =   \cancel\frac{6}{4}   \\  \\ \mapsto  \bf\blue{k =  \frac{3}{2}} \\\\

K = 3/2 in both cases.

So,

The required ratio is 3/2:1

which is 3:1.

Hence ,

(-6 ,5) divides the line segment joining (-3,-1) and (-8,9) in the ratio of 3:2.

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