I need help guys Only serious answers)

If f(x)= sqrt4x+9+2, which inequality can be used to find the domain of f(x)?

Sundar used linear combination to solve the system of equations shown. he did so by multiplying the first equation by 5 and the second equation by another number to eliminate the y-terms. what number did sundar multiply the second equation by? 2x+9y=41 3x+5y=36

Can someone show me step by step how to do this?