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anonymous

  • 5 years ago

can anyone help me with solving problems using quadratic functions?

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  1. amistre64
    • 5 years ago
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    ..... same stuff eh :)

  2. amistre64
    • 5 years ago
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    whatcha got....

  3. anonymous
    • 5 years ago
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    The company discovered that it costs $45 to produce 2 calculators, $143 to produce 4 calculators, and $869 to produce 10 calculators. Using quadratic functions, find the cost of producing 7 calculators.

  4. amistre64
    • 5 years ago
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    :) ill try this the elimination way this time and see what I get ;)

  5. amistre64
    • 5 years ago
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    4a + 2b +c= 45 4a + 2b +c= 45 16a + 4b +c = 143 100a +10b +c = 869 (1/4) 4a + 2b +c= 45 4a + 2b +c= 45 16a + 4b +c = 143 100a +10b +c = 869 (-16) 1a + b/2 + c/4= 45/4 (-100) 1a + b/2 +c/4= 45/4 16a + 4b +c = 143 100a +10b +c = 869 -16a - 8b - 4c= -180 -100a - 50b -25c= -1125 16a + 4b + c = 143 100a + 10b + c = 869 ---------------------- --------------------- -4b -3c = -37 -40b -24c = -256

  6. amistre64
    • 5 years ago
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    (-1/4) -4b - 3c = -37 -40b -24c = -256 (40) b + 3c/4 = 37/4 -40b -24c = -256 40b + 30c = 370 -40b -24c = -256 --------------------- 6c = 114 c = 19

  7. anonymous
    • 5 years ago
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    19 in the answer?

  8. amistre64
    • 5 years ago
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    no, 19 is part of the quadratic equation ...like this: ax^2 +bx +19 = y

  9. amistre64
    • 5 years ago
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    -40b -24c = -256 -40b -24(19) = -256 -40b -456 = -256 -40b = -256 +456 -40b = 200 b = -5 ax^2 -5x + 19 = y so far ;)

  10. amistre64
    • 5 years ago
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    4a + 2(-5) +19= 45 4a -10 +19 = 45 4a = 45 +10 -19 4a = 36 a = 36/4 = 9 y = 9x^2 -5x + 19; now what does this equal when x = 7?

  11. amistre64
    • 5 years ago
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    y = 9(7)^2 -5(7) + 19 y = 9(49) -35 +19 y = $425 for 7 cameras

  12. amistre64
    • 5 years ago
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    going over the math to se if I am right...

  13. anonymous
    • 5 years ago
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    you were (: a rock is launched from a cannon. after one second, the rock is 58 feet in the air; after 2 seconds the rock is 112 feet in the air. find the height, in feet, of the rock after 10 seconds in the air.

  14. amistre64
    • 5 years ago
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    yay!!

  15. amistre64
    • 5 years ago
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    so we have 2 points, 1,58 and 2,112, were missing a 3rd point.....but are we? the third point is at time=0 the position of our rock is at a heaight of 0 so we have our 3rd point (0,0) 0a +0b +c = 0..... c = 0 that was easy enough for that one :) 1a +1b = 58 4a +2b = 112 a = 58-b so just substitute that back into the secnd one... 4(58-b) +2b = 112 232 -4b+2b = 112 -2b = 112 -232 b = -120/-2 = 60 b = 60 -------------------- a = 58-b a = 58-60 = -2 y = -2x^2 +60x y = -2(x^2 -30x) when x=10... y = -2((10)^2 -30(10)) y = -2(100-300) y = -2(-200) y = 400 ...let me recheck my work ;)

  16. amistre64
    • 5 years ago
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    it checks out...

  17. anonymous
    • 5 years ago
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    correct! (:

  18. amistre64
    • 5 years ago
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    i missed 3 questions on my trig test monday..... simple mistakes really, forgot to look at sign changes and even had right answers but wrong answer circled....

  19. anonymous
    • 5 years ago
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    that's my problem usually too! The company discovered that it costs $45 to produce 4 camera cases, $257 to produce 7 camera cases, and $792 to produce 12 camera cases. Using quadratic function, find the cost of producing 1 camera case.

  20. amistre64
    • 5 years ago
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    i wonder if I can write a formula for this to make things easier on me :)

  21. anonymous
    • 5 years ago
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    possibly. it doesn't give me one to use on any of these.

  22. amistre64
    • 5 years ago
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    ill go to the other posting you did.... and try my matrix skills :)

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