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1 year ago

Solve the system of equations.

D20x-400%7D%7D%20%5Cright.%20%5C%5C" id="TexFormula1" title="\left \{ {{y=220x-160} \atop {y=20x-400}} \right. \\" alt="\left \{ {{y=220x-160} \atop {y=20x-400}} \right. \\" align="absmiddle" class="latex-formula">

Mathematics

1 answer:

Leni [432]1 year ago

4 0

$\begin{cases} y=220x-160\\ y=20x^2-400 \end{cases}\qquad \qquad \stackrel{\textit{substituting on the 2nd equation}}{\stackrel{\textit{\Large y}}{220x-160}~~ = ~~20x^2-400} \\\\\\ -160=20x^2-220x-400\implies 0=20x^2-220x-240 \\\\\\ 0=20(x^2-11x-12)\implies 0=x^2-11x-12 \\\\\\ 0=(x-12)(x+1)\implies x= \begin{cases} 12\\ -1 \end{cases}$

$\dotfill\\\\ x=12\qquad \qquad \stackrel{\textit{substituting on the 1st equation}}{y=220(12)-160}\implies y=2480 \\\\\\ x=-1\qquad \qquad \stackrel{\textit{substituting on the 1st equation}}{y=220(-1)-160}\implies y=-380 \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill (12~~,~~2480)\qquad (-1~~,~~-380)~\hfill$

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2 years ago

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tia_tia [17]

Answer:

84 ounces of pure gold

Step-by-step explanation:

Jess has 60 ounces of an alloy that is 40% gold. How many ounces of pure gold must be added to this alloy to create a new alloy that is 75% gold?

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Let the number of ounces of pure gold = x

Hence, we have the equation

40% × 60 ounces + 100%× x ounces = 75%(60 + x)ounces

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2 years ago

Can u help me with this?

sattari [20]

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2 years ago

Which of the following describes the probability distribution below?

Serhud [2]

Answer:

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Step-by-step explanation:

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2 years ago

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Answer:

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2 years ago