Solve for x:
x + 3x - 19 = 17

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 - We combine the variables because to get to the end sum of the equation, there can only be 1 variable. So to get the 1, you combine like terms.

 - We do this to get 1 number left over. To do this you do the opposite of what you see. In this case we have a negative 19, so you add 19 on each side of the equals.

 - We do this to get x alone. To do this you do the opposite of what you see. In this case we have which is multiplying, so you divide by 4 on each side.

So your answer is .

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yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value

here is the

mark brainliest pl