Question Number 68237 by smartsmith459@gmail.com last updated on 07/Sep/19
$$\mathrm{1}.\:{find}\:{the}\:{equation}\:{of}\:{the}\:{line}\:{making}\:{an}\:{angle}\:{of}\:\mathrm{135}^{°\:} {with}\:{O}_{{x}\:} \:{and}\:{passing}\:{through}\:{thepoints}?\left(−\mathrm{2},\mathrm{5}\right) \\ $$$$\mathrm{2}.\:{find}\:{the}\:{slope}\:{of}\:{the}\:{line}\:{through}\:{the}\:{points}\:\left(\mathrm{5},\mathrm{3}\right){and}\:\left(\mathrm{7},\mathrm{2}\right).\:{find}\:\left({i}\right)\:{the}\:{perpendicular}\:{form}\:\left({ii}\right)\:{find}\:{the}\:{intercept}\:{form}\:{of}\:{its}\:{equation}. \\ $$$$\mathrm{3}.\:{Determine}\:{the}\:{gradient}\:{of}\:{the}\:{straight}\:{line}\:{graph}\:{passing}\:{through}\:{the}\:{co}-{ordinates}: \\ $$$$\left({i}\right)\:\left(\mathrm{2},\mathrm{7}\right)\:{and}\:\left(−\mathrm{3},\mathrm{4}\right) \\ $$$$\left({ii}\right)\:\left(\frac{\mathrm{1}\:}{\mathrm{4}},\:\frac{-\mathrm{3}}{\mathrm{4}}\right)\:{and}\:\left(\frac{-\mathrm{1}}{\mathrm{2}},\:\frac{\mathrm{5}}{\mathrm{8}}\right). \\ $$
Commented by kaivan.ahmadi last updated on 07/Sep/19
$$\mathrm{1}. \\ $$$${m}={tan}\mathrm{135}={tan}\left(\mathrm{90}+\mathrm{45}\right)=−{cot}\mathrm{45}=−\frac{\sqrt{\mathrm{2}}}{\mathrm{2}} \\ $$$${y}−\mathrm{5}=−\frac{\sqrt{\mathrm{2}}}{\mathrm{2}}\left({x}+\mathrm{2}\right)\Rightarrow{y}=−\frac{\sqrt{\mathrm{2}}}{\mathrm{2}}{x}+\left(\mathrm{5}−\sqrt{\mathrm{2}}\right) \\ $$$$\mathrm{2}. \\ $$$${m}=\frac{\mathrm{3}−\mathrm{2}}{\mathrm{5}−\mathrm{7}}=−\frac{\mathrm{1}}{\mathrm{2}} \\ $$$${y}−\mathrm{3}=−\frac{\mathrm{1}}{\mathrm{2}}\left({x}−\mathrm{5}\right)\Rightarrow{y}=−\frac{\mathrm{1}}{\mathrm{2}}{x}+\frac{\mathrm{11}}{\mathrm{2}} \\ $$$${perpendicular}\:{slope}\:\:{m}_{\mathrm{1}} =\mathrm{2} \\ $$$$\mathrm{3}. \\ $$$$\left({i}\right). \\ $$$${y}−\mathrm{7}=\frac{\mathrm{4}−\mathrm{7}}{−\mathrm{3}−\mathrm{2}}\left({x}−\mathrm{2}\right)\Rightarrow{y}=\frac{\mathrm{3}}{\mathrm{5}}{x}+\frac{\mathrm{29}}{\mathrm{5}}\Rightarrow \\ $$$${f}\left({x},{y}\right)=\mathrm{3}{x}−\mathrm{5}{y}+\mathrm{29}=\mathrm{0} \\ $$$$\bigtriangledown{f}=\left(\mathrm{3},−\mathrm{5}\right) \\ $$$$ \\ $$