Question

Here ya go these are the ones i need help with :)

Answer 1

1) Division Property Equality
$8D = 56$
first pass: Simplify by 8
$\frac{8D}{8} = \frac{56}{8}$
second pass: Now divide the equals
$1D= 7$
$D = \frac{7}{1}$
$\boxed{D = 7}$

2) Addition Property of Equality
$Z - 9 = 21$
first pass: Incognito on the left and numbers without incognito on the right, changing signs if they change sides.
$Z = 21 + 9$
second pass: Do the addition
$Z = 21 + 9$
$\boxed{Z = 30}$

3) Subtraction Property of Equality
$B + 7 = 15$
first pass: Incognito on the left and numbers without incognito on the right, changing signs if they change sides.
$B = 15 - 7$
second pass: Do the subtraction
$B = 15 - 7$
$\boxed{B = 8}$

4) Multiplication Property of Equality
$\frac{3}{7} C = 126$
first pass: Multiply the equalities by the inverse of the incognito, without the incognito
$( \frac{7}{3}) *\frac{3}{7} C = 126*( \frac{7}{3})$
$\frac{21}{21} C = \frac{882}{3}$
second pass: Cancel the same terms and divide the ratio.
$\frac{\diagup\!\!\!\!\!21}{\diagup\!\!\!\!\!21} C = \frac{882}{3}$
$C = \frac{882}{3}$
$\boxed{C = 294}$

5) Distributive Property
first pass: We only evaluate what is in the parentheses first and then we solve it.
$7(A+13)$
second pass: we just evaluate what’s in the parentheses first, then solve it. We have a distributive property, with the distributive property, we multiply the '7' first.
$7*A + 7*13$
$7A + 91$

Obs: This question is not to find the value, only to show the distributive property.

For better understanding and solve your question with equation with incognito, after the distributive property, equalize the terms to zero, then isolate the terms, putting numbers with incognito on the left and numbers without incognito on the right, changing the signal as they change sides. And then solve by finding the value of the incognito dividing the terms.
$7A + 91 = 0$
$7A = - 91$
$A = \frac{-91}{7}$
$\boxed{A = - 13}$