Joanie believes that you cannot use cross products to solve the proportion StartFraction 50 over 3 EndFraction = StartFraction 75 over x EndFraction for x. She says that if you multiply both sides of the equation by x, you get StartFraction 50 x over 3 EndFraction = 75. Then, if you multiply both sides of the equation by 3, you get 50 x = 75, which is a different equation than you would get if you cross multiplied. What mistake did Joanie make in her reasoning? She assumed that the multiplication property of equality allows her to multiply both sides of the equation StartFraction 50 over 3 EndFraction = StartFraction 75 over x EndFraction by x.
She assumed that the multiplication property of equality allows her to multiply both sides of the equation StartFraction 50 x over 3 EndFraction = 75 by 3.
She assumed that 50 x = 75 is the equation that you get if you multiply both sides of the equation StartFraction 50 x over 3 EndFraction = 75 by 3.
She assumed that 50 x = 75 is a different equation than you would get if you cross multiplied to solve the proportion StartFraction 50 over 3 EndFraction = StartFraction 75 over x EndFraction for x.