Let's solve each equation step-by-step.

Problem a

$10x - 7 = 13$

1. Add 7 to both sides: $10x = 20$
2. Divide by 10: $x = 2$

Solution: $x = 2$

Problem b

$5 + 4x = 29$

1. Subtract 5 from both sides: $4x = 24$
2. Divide by 4: $x = 6$

Solution: $x = 6$

Problem c

$-4x + 9 = -19$

1. Subtract 9 from both sides: $-4x = -28$
2. Divide by -4: $x = 7$

Solution: $x = 7$

Problem d

$6 - \frac{x}{5} = 0$

1. Subtract 6 from both sides: $-\frac{x}{5} = -6$
2. Multiply by -5: $x = 30$

Solution: $x = 30$

Let me know if you would like further explanation on any of these steps!

Here are some related questions:

1. How would you solve for $x$ if there was a fraction on both sides of the equation?
2. What happens if you encounter an equation where $x$ has an exponent, like $x^2$?
3. Can these steps be applied to equations with variables on both sides?
4. How do we solve an inequality instead of an equation?
5. What if there's more than one variable, like in a system of equations?

Tip: Always isolate the variable by reversing the operations applied to it, step-by-step.