Requirements for proofs in a logical system

Jeremiah and Tristan work at a dry cleaners ironing shirts. Jeremiah can iron 35 shirts per hour, and Tristan can iron 20 shirts per hour. Jeremiah and Tristan worked a combined 17 hours and ironed 490 shirts.

Identify the value for the variable. What is the value of x in this simplified expression? 7-9 · 7-3 = 7x x = What is the value of y in this simplified expression?

Find the two horizontal and two vertical tangent lines of the equation x^2+xy+y^2=9.

Urgent if x=-3 and y=2 find the value of: 5x + 4y

If 18% of all Americans are underweight, find the probability that if 3 Americans were selected at random, all will be underweight.

If 4+6+7=242854 6+6+7=364217 6+7+8=424828then 7+5+8=?

the numbers 30 to 74 are in a hat. If the probability of drawing a multiple of 2 is 23/45. What is the probability of not drawing a multiple of two?

What is the value of p? p+1/5-1/2=1/10

An orchestra of 120 players takes 40 minutes to preform a symphony. How long will it take for 60 players to preform the symphony

Name the next two numbers in the series: 128, 64, 16 ...