1. if y=mx+1, -mx+y=1, 3x+4y=9 find out the value of m.
2. sum of 2 digits is 9. the digit obtained by7 increasing digit in ten's place by unity is one ninth of the no.obtained. find the no.
for 1. are the two lines supposed to be parallel?
then ...
for y = mx + 1, slope = m
for 3x + 4y = 9 , slope = -3/4
so m = -3/4
2. no idea what you mean. Is there a 2-digit number?