(+7) - (+4)
Can I get an explanation and answer? To how someone got it?

Is this a polynomial function? i need to know asap

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

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.