Answer 1

9 - 4x ≤ 15 - 7x 

9 - 4x ≤15 - 7x 

9 - 15 ≤ 4x - 7x 

-6 ≤ -3x 

6 ≥ 3x ( multiplying by -1 changes the sign) 

x ≥ 2

Since, replacement set is R

Solution set= {x : x ∈ R and x ≤ 2}