A student claims that he can solve 12x + 8y = 40 and 4x + 5y = 18 for x and y by adding the first equation to a multiple of the second equation. He can then use the new equation and the first equation to create a new system that has the same solution as the original system. The student begins by listing four different equations.
Determine whether the student can use that equation to replace the second equation and create a new system that has the same solution. Select Yes or No for each equation.
PLEASE PROVIDE WORK!!! AND QUICLY BECAUSE ITS TIMED! THANKS

Browning labs is testing a new growth inhibitor for a certain type of bacteria. the bacteria naturally grows exponentially each hour at a rate of 6.2%. the researchers know that the inhibitor will make the growth rate of the bacteria less than or equal to its natural growth rate. the sample currently contains 100 bacteria. the container holding the sample can hold only 300 bacteria, after which the sample will no longer grow. however, the researchers are increasing the size of the container at a constant rate allowing the container to hold 100 more bacteria each hour. they would like to determine the possible number of bacteria in the container over time. create a system of inequalities to model the situation above, and use it to determine how many of the solutions are viable.

What is the rate of change of a line that passes through (2,-5) and (6,-2)?

Find the area of the triangle shown 3 by 6