Help and i will give brainiest if you answer them all if random will report answer all of them

Landon wrote that 3−2.6=4. which statement about his answer is true?

The students at jefferson middle school are raising money for a charity by selling t-shirts and hats. the number of t-shirts sold was 3 times the number of hats. the profit was $5 for each t-shirt sold and $2.50 for each hat sold. the students raised $840 for the charity. they used the system below to analyze their success and found the solution to be (144, 48). 5x+2.50y=840 x=3y how much did they earn from t-shirt sales?

Let f of x equals the integral from 1 to 3 times x of the natural logarithm of t squared. use your calculator to find f″(1).