Respuesta :

Answer:
d. 21

Explanation:
Step 1 - Subtract 13 from both sides
x + 13 = 34
x + 13 - 13 = 34 - 13
x = 21

Answer:

21

Step-by-step explanation:

since we are looking for the value of x, we make it the subject of the formula(stand alone) and to do that + 13 would have to cross over the equality sign.when a positive number crosses over the equality sign it changes to a negative number .

Therefore,x +13=34

x=34 -13

x=21(d)