Help me understand standard form?

i know that standard form is Ax + By + C = 0, but i'm having trouble understanding what values you would plug into the equation.





lets say that the equation is y=9x+5

Help me understand standard form?
are you sure this is standard form cuz when I learnt it it wasnt nothin like this..





Standard form is a way of writing down very large or very small numbers easily. 10³ = 1000, so 4 × 10³ = 4000 . So 4000 can be written as 4 × 10³ . This idea can be used to write even larger numbers down easily in standard form.





The rules when writing a number in standard form is that first you write down a number between 1 and 10, then you write × 10(to the power of a number).





Example


Write 81 900 000 000 000 in standard form:





81 900 000 000 000 = 8.19 × 1013





It’s 1013 because the decimal point has been moved 13 places to the left to get the number to be 8.19





Example


Write 0.000 001 2 in standard form:





0.000 001 2 = 1.2 × 10-6





It’s 10-6 because the decimal point has been moved 6 places to the right to get the number to be 1.2





On a calculator, you usually enter a number in standard form as follows:


Type in the first number (the one between 1 and 10). Press EXP . Type in the power to which the 10 is risen.