Вправи: 1236

1236. Склади рівняння прямої виду у = kx + p, яка проходить через

точки:

а) А(1; 3) і В(3; 7);y = kx + p; k • 1 + p = 3; k • 3 + p = 7; k + p = 3|• (–3); 3k + p = 7;+ –3k – 3p = –9; 3k + p = 7;–2p = –2;p = 1.k = 3 – p = 3 – 1 = 2;y = 2x + 1.в) C(2; 4) i D(5; –2); k • 2 + p = 4; k • + p = –2; 2k + p = 4; 5k + p = –2|• (–1);+ 2k + p = 4; –5 – p = 2;–3k = 6;k = –2;p = 4 – 2k = 4 – 2 • (–2) = 8;y = –2x + 8.

б) К(3; 2) і З(–1; –2);y = kx + p; k • 3 + p = 2; k • (–1) + p = –2; 3k + p = 2; –k + p = –2|• 3;+ 3k + p = 2; –3k + 3p = –6;4p = –4;p = –1.k = 2 + p = 2 – 1 = 1;y = x – 1.г) E(1; 2) i F(3; 3); k • 1 + p = 2; k • 3 + p = 3; k + p = 2|• (–1); 3k + p = 3;+ –k – p = –2; 3k + p = 3;2k = 1;k = 0,5.p = 2 – k = 2 – 0,5 = 1,5;y = 0,5x + 1,5.