Ex 9.2, 7 - Chapter 9 Class 11 Straight Lines

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Ex 9.2, 7 Find the equation of the line which passes through the points (–1, 1) and (2, –4). We know that equation of line through two points (x1, y1) & (x2, y2) is 𝑦 – 𝑦_1 = (𝑦_2 − 𝑦_1)/(𝑥_2 − 𝑥_1 ) (𝑥 – 𝑥_1) Since equation of the line through the points (−1, 1) and (2, –4). Here, x1 = −1, y1 = 1 & x2 = 2, y2 = –4 Putting values (y – 1) = ( −4 − 1)/(2 − ( −1)) (x – (−1)) (y – 1) = ( −5)/(2 + 1) (x + 1) (y – 1) = ( −5)/3 (x + 1) 3(y – 1) = −5(x + 1) 3y – 3 = −5x – 5 5x + 3y + 2 = 0 Hence, the required equation is 5x + 3y + 2 = 0