Ex 3.7, 7 (Optional) - Chapter 3 Class 10 Pair of Linear Equations in Two Variables - Part 17

Ex 3.7, 7 (Optional) - Chapter 3 Class 10 Pair of Linear Equations in Two Variables - Part 18
Ex 3.7, 7 (Optional) - Chapter 3 Class 10 Pair of Linear Equations in Two Variables - Part 19

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Transcript

Question 7 Solve the following pair of linear equations: (v) 152x – 378y = – 74 –378x + 152y = – 604 152x − 378y = −74 …(1) −378x + 152y = −604 …(2) From equation (1) 152x – 378y = −74 378y = 152x + 74 y = (152𝑥 + 74)/378 y = (2(76𝑥 + 37))/(2(189)) y = (76𝑥 + 37)/189 Put y = (76𝑥 + 37)/189 in equation (2) −378x + 152y = −604 −378x + 152[(76𝑥 + 37)/189] = −604 −378x + [(152(76𝑥) +152 × 37)/189] = −604 −378x + [(11552𝑥 + 5624)/189] = −604 Multiplying 189 both sides 189(−378x) + 189[(11552𝑥 + 5624)/189] = 189(−604) −71442x + 11552x + 5624 = −114156 11552x − 71442 x = −114156 − 5624 −59890x = −119780 x = (−119780)/(−59890) x = 2 Putting x = 2 in equation (3) y = (76 × 2 + 37)/189 y = (152 + 37)/189 y = 189/189 y = 1 Therefore, x = 2 and y = 1.

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.