Tutor profile: Alysa M.
When do you use preterit vs imperfect form?
Preterit is used for actions that have a definite ending and beginning, usually viewed as single events. For example, "Yesterday I went to the store." Ayer fui a la tienda. Whereas, imperfect there is no definite ending, or the actions are not yet completed. For example, "When I was little, I used to play with dolls." Cuando era niña, jugaba con muñecas. There are words to look out for the give you a hint of when to use preterit or imperfect. In the first sentence the word is "yesterday," this helps give a specific time frame for the action.
A neutral element has a mass number of 129 and 75 neutrons. What is the identity of this element?
Mass number of an element is the number of protons and neutrons in an atom of the element. Subtracting the 75 neutrons from the mass number gives the atomic number of the element, which in this case is 54. Looking at the periodic table, the element with the atomic number 54 is Xenon.
What is the slope of a line perpendicular to the line x = -3?
First, we'll look at the slope for the line of x = -3, the slope for this line is undefined, because it is vertical. A line that is perpendicular to the line of x = -3 (should create a "T" shape), it will be a horizontal line. A complete horizontal line has a slope of 0, therefore, the slope of the line perpendicular to the line x = -3 is 0.
needs and Alysa will reply soon.