1) What is the reciprocal of 9/1? 2) If 5x+ y = 7 and x+ 2y = 5 what is the valu

Question

1) What is the reciprocal of 9/1?

2) If 5x+ y = 7 and x+ 2y = 5 what is the value of x & y?

3) 4 - 8 - (-8) + 4 = ____________

4) 200 is what percent of 25?

5) 50 lbs            20 lbs

        .__________.

              10m                 Where is the location of 50 lbs to balance the weight into the 10m lever?

Explanation / Answer

1. 1/9. "reciprocal" pretty much means flip the fraction. the initial numerator is the final denominator, and the initial denominator is now the final numerator. 2. 5x+y=7 --> y=7-5x (use substitution here. plug in "7-5x" for y in the second equation: x+2y=5) x+2(7-5x)=5 x+14-10x=5 -9x=-9 x=1 (now plus this value into either of the original equations (I'm using the first equation here) in order to find the y value) 5x+y=7 5(1)+y=7 5+y=7 y=2 3. 4-8-(-8)+4=? (A number minus a negative number is really just adding a positive number. In a sense, the two negative signs "cancel" each other out.) 4-8+8+4=? 4+4=8 4. 200=25x (this is how you set up this problem. In these types of problems, you have to be in top of that wording or else you'll multiply the wrong number and get a crazy percentage. In this case, I like to think of quarters (the money kind). Eight quarters makes up two dollars. So, x=8. In order to get the percentage, multiply x times 100.) 200 is 800% of 25. 5. Sorry I'm not too certain about this one, but I'm guessing that the 50lb weight will be roughly 2/5 across the 10m board in order for the system to be at equilibrium. I say this because 20lb is 40% of 50lbs and so the 50lb weight would have to make up for that distance. I say the 50lb weight is 4m into the 10m board.

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