math
posted by Tracy on .
solve
14is less then and equal to 3x 7less than and equal to 2

Write
14 <= 3x7 <= 2
or
14 ≤ 3x7 ≤ 2
(≤ is written as "& l e ;" without the double quotes and without spaces).
There are two inequalities. We need to solve each one separately and find the solution interval that satisfies both inequalities.
14 ≤ 3x7
=> 3x7 ≥ 14
=> 3x ≥ 14 + 7 = 7
=> x ≥ 7/3
3x7 ≤ 2
=> 3x ≤ 2+7 = 5
=> x ≤ 5/3
Take the most restrictive interval to give
7/3 ≤ x ≤ 5/3
Check the solution by substituting it back to the original inequalities.