To solve this, take a look at the images provided and first find out the number of polygons out of the total number of cards given which would be 3 polygons out of 5 cards, which would be better represented as the fraction 3/5. Now, the question asks to find the probability of Julie picking a card that shows a polygon, and since 3 out of 5 of the cards are polygons, your answer would be 3/5.
First of all, x cannot ever equal -1 because if it does then in the original equation you'd be dividing by 0, which is not possible. anything divided by 0 is undefined.
I think the error was in the second step: x(x+1) = 2(x+1) because they didn't need to go from the first step to there. I'm assuming they multiplied both sides of the equation with (x+1) to get rid of the fraction, but since both sides have (x+1) as the denominator the (x+1) would've cancelled out instead of multiplying with the numerator.
Correction:

as u can see, in the second step of this correction, the (x+1)s on both sides cancel out so only the numerators remain.
Hope this helps!
Answer:
400 is the answer
Step-by-step explanation:
Please use a calculator if your teacher says too. Write the two number under each other like this
100+
300
I hope this helps!
Answer:
In this equation "a" is a variable.
Step-by-step explanation:
A variable is a term used that does not necessary have a value attached to it. Instead any value can be input in for it.