Ihave solving systems of equations using substitution, and sometimes i have equations like this: 12x-5y=-20y=x+4and then stuff like this: 2x+7y=3x=-4yit's kind of hard to know how to do a lot of different equations for one topic, could someone show me how to do all the different kinds

Which expression and diagram represent “renee biked four times as far this month as last month”?

What is the simplified form of 400x100 ? o 200x10 o 200x50 0 20x10 • 20x50

(co 3) the times that customers spend in a book store are normally distributed with a mean of 39.5 minutes and a standard deviation of 9.4 minutes. a random sample of 25 customers has a mean of 36.1 minutes or less. would this outcome be considered unusual, so that the store should reconsider its displays? no, the probability of this outcome at 0.035, would be considered usual, so there is no problem yes, the probability of this outcome at 0.035, would be considered unusual, so the display should be redone no the probability of this outcome at 0.359 would be considered usual, so there is no problem yes, the probability of this outcome at 0.965 would be considered unusual, so the display should be redone