Step-by-step explanation:
substitution is when you replace x with a number to find y, or vice versa. there is not one answer when doing this, its a series of answers.
for your question y=2x+1, we can substitue x with any number to find out y. any number, it can be random but i suggest starting with 1. you can also do negatives but like i said, 1 is the most basic.
Once you substitute x with 1, the equation turns to 2 times 1, since we substitued.
when x is next to a number, it means to multiply it.
2 times 1 is 2, and then '+1', is 3.
you can substitute this again with different numbers
example, if you subbed with 5, it would be
2 times 5, which is 10, +1 which is 11. that means y is 11.
this is the same method you can use for the second question. remember to substitute with atleast 5 numbers for your teacher to see :)
