(a)[3]
Set up an equation and solve it to determine the value of $x$.
(b)[3]
Determine the integer values of $t$ that satisfy the inequalities $4t + 7 < 39 \le 7t + 2$.
(c(i))[3]
Solve $\frac{21 - x}{x + 3} = 4$.
(c(ii))[4]
Solve $3x^2 + 7x - 5 = 0$.