Algebra
# Linear Inequalities

If $x+y = 7$ and $4 \leq x \leq 19,$ what is the range of $y?$

If the inequality $a^2(x+1)>576 x+24a$ holds for all real numbers $x,$ what is the constant $a?$

Real numbers $x$ and $y$ satisfy $-3 < x < 1$ and $-1 < y < 5$. What is the range of $x - y ?$