Textbook Problem

Predict whether each of the following pairs of equations represents parallel lines, perpendicular lines, or lines that intersect but are not perpendicular. Then graph each pair of lines to check your predictions. (The properties presented in Problem 83 should be very helpful.

(a) $5.2x+3.3y=9.4$ and $5.2x+3.3y=12.6$

(b) $1.3x-4.7y=3.4$ and $1.3x-4.7y=11.6$

(c) $2.7x+3.9y=1.4$ and $2.7x-3.9y=8.2$

(d) $5x-7y=17$ and $7x+5y=19$

(e) $9x+2y=14$ and $2x+9y=17$

(f) $2.1x+3.4y=11.7$ and $3.4x+2.1y=17.3$

(g) $7.1x-2.3y=6.2$ and $2.3x+7.1y=9.9$

(h) $-3x+9y=12$ and $9x-3y=14$

(i) $2.6x-5.3y=3.4$ and $5.2x-10.6y=19.2$

(j) $4.8x-5.6y=3.4$ and $6.1x+7.6y=12.3$