1. if y=mx+1, -mx+y=1, 3x+4y=9 find out the value of m.

Question

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.

Answer 1

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?