HI i know i am a week late but i hope this helps in some way. :)
X = Mateo Trading cards
4x-7 = Camila Treading cards
(4x-7) +x>51
4x-7+x>51
5x-7>51
5x>51+7
5x>58
x>58/5
x>11.6 = 12
Mateo can have at least 12 trading cards
Answer:
19.9 miles
Step-by-step explanation:
In this problem we have:
is the distance travelled during the 1st day
is the distance travelled during the 2nd day
is the distance travelled during the 3rd day
is the distance travelled during the 4th day
We notice that the difference between the distance travelled on the (n+1)-th day and the distance travelled on the n-th day doubles every day. In fact:

Which can be rewritten using the general formula:

This means that

By applying this formula recursively, we can find the 7th term, which is the distance travelled on the 7th day:

So, the distance travelled on the 7th day is 19.9 miles.
X + (2x + 7) = 121 : Write the expression.
3x + 7 = 121 : Combine like terms.
3x + 7 - 7 = 121 - 7 : Isolate x.
3x = 114 : Combined like terms.
3x / 3 = 114 / 3 : Find the value of x.
x = 38 : This is the smaller integer.
(2x + 7) = (2(38) + 7) = 76 + 7 = 83. : Find the value of the larger number by plugging in the value of x to the larger number's quantity.
The larger number is 83, and the smaller number is 38.