A scientist conducted an experiment and discovered that certain plants grow faster when you give me a particular amount of fertilizer another scientist conducted the same experiment and got a similar results which concept does this best illustrate

Pls , the question is in the picture!

John used linear combination to solve the system of equations shown. he did so by multiplying the first equation by -3 and the second equation by another number to eliminate the x-terms. what number did jonas multiply the second equation by? 4x-6y=23x+5y=11

2.5 milligrams is equivalent to how many grams