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2 years ago

Which inequality is true for x =20

Mathematics

1 answer:

Tanzania [10]2 years ago

5 0

I don't think this is a full mathematical question, comment more so I can understand

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The sum of two numbers is 9.9, and the sum of the squares of the numbers is 53.21. What are the numbers?

Snezhnost [94]

Answer:

There are two possibilities:

$x_{1} = 3.5$ and $y_{1} = 6.4$

$x_{2} = 6.4$ and $y_{2} = 3.5$

Step-by-step explanation:

Mathematically speaking, the statement is equivalent to this 2-variable non-linear system:

$x + y = 9.9$

$x^{2} + y^{2} = 53.21$

First, $x$ is cleared in the first equation:

$x = 9.9 - y$

Now, the variable is substituted in the second one:

$(9.9-y)^{2} + y^{2} = 53.21$

And some algebra is done in order to simplify the expression:

$98.01-19.8\cdot y +2\cdot y^{2} = 53.21$

$2\cdot y^{2} -19.8\cdot y +44.8 = 0$

Roots are found by means of the General Equation for Second-Order Polynomials:

$y_{1} \approx \frac{32}{5}$ and $y_{2} \approx \frac{7}{2}$

There are two different values for $x$ :

$y = y_{1}$

$x_{1} = 9.9-6.4$

$x_{1} = 3.5$

$y = y_{2}$

$x_{2} = 9.9 - 3.5$

$x_{2} = 6.4$

There are two possibilities:

$x_{1} = 3.5$ and $y_{1} = 6.4$

$x_{2} = 6.4$ and $y_{2} = 3.5$

5 0

2 years ago

Solve for x<br><img src="https://tex.z-dn.net/?f=4%20%20%7Bx%7D%5E%7B2%7D%20%20%3D%207x%20%2B%202" id="TexFormula1" title="4 {x

Alina [70]

$\bf 4x^2=7x+2\implies 4x^2-7x-2=0\implies (4x+1)(x-2)=0 \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ 4x\cdot x=\boxed{4x^2}~\hfill (1)(-2)=\boxed{-2}\hfill (4x\cdot -2)+(1\cdot x)=\boxed{-7x} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \begin{cases} 4x+1=0\implies 4x=-1\implies &x=-\cfrac{1}{4}\\[1em] x-2=0\implies &x=2 \end{cases}$