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2 years ago

-7x - 2y = 19 4x + y = -12 Solve the system

Mathematics

1 answer:

nalin [4]2 years ago

4 0

-7x - 2y = 19

4x + y = -12

Set y equal to each other (opposite signs are fine and you could also set x equal instead of y)

-7x - 2y = 19

8x + 2y = -76

Add equations together

x = -52

Plug x value into an equation

4(-52) + y = -12

Solve for y

-208 + y = -12

y = 196

Hope this helps! ;)

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jeyben [28]

Answer:

29.28 degrees.

Step-by-step explanation:

sin x / 16.2 = sin 49 / 25

Cross multiply:

25 sin x = 16.2 * sin 49

sin x = (16.2 * sin 49) / 25

sin x = 0.48905

x = 29.28 degrees.

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3 years ago

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2 years ago

Write an equation that represents the line.<br> Use exact numbers.<br> (-2,-1)<br> (4,6)

vazorg [7]

Check the picture below.

to get the equation of any straight line, we simply need two points off of it, so let's use those in the picture

$(\stackrel{x_1}{-2}~,~\stackrel{y_1}{1})\qquad (\stackrel{x_2}{4}~,~\stackrel{y_2}{6})~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{6}-\stackrel{y1}{1}}}{\underset{run} {\underset{x_2}{4}-\underset{x_1}{(-2)}}} \implies \cfrac{6 -1}{4 +2} \implies \cfrac{ 5 }{ 6 }$

$\begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{1}=\stackrel{m}{\cfrac{5}{6}}(x-\stackrel{x_1}{(-2)})\implies y-1=\cfrac{5}{6}(x+2) \\\\\\ y-1=\cfrac{5}{6}x+\cfrac{5}{3}\implies y=\cfrac{5}{6}x+\cfrac{5}{3}+1\implies y=\cfrac{5}{6}x+\cfrac{8}{3}$

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1 year ago

Please help and show all work so I can fully understand it, thanks.

seraphim [82]

Answer:

$\frac{1}{m-4}$

Step-by-step explanation:

$\frac{\frac{4m-5}{m^4 -7m^3 +12m^2}}{\frac{4m-5}{m^3 -3m^2}}$

Factor the equation:

$\frac{\frac{4m-5}{m^2(m^2 -7m+12)}}{\frac{4m-5}{m^2(m-3)}}$

$\frac{\frac{4m-5}{m^2(m-3)(m-4)}}{\frac{4m-5}{m^2(m-3)}}$

Rewrite to suit the format of multiplying two fractions. Remember, dividing two fractions is the same as multiplying the first fraction by the reciprocal of the second. A reciprocal of a fraction is when one switches the place of the numerator and the denominator, that is, the value on top (numerator), and the value on the bottom (denominator).

$\frac{4m-5}{m^2(m-3)(m-4)}*\frac{m^2(m-3)}{4m-5}$

Simplify, take out common terms that are found on both the numerator and denominator

$\frac{4m-5}{m^2(m-3)(m-4)}*\frac{m^2(m-3)}{4m-5}$

$\frac{1}{m-4}$

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2 years ago

Consider the following pair of equations:

Zinaida [17]

Answer:

The lines representing these equations intercept at the point (-4,2) on the plane.

Step-by-step explanation:

When we want to find were both lines intercept, we are trying to find a pair of values (x,y) that belongs to both equations, which means that it satisfies both equations at the same time.

Therefore, we can use the second equation that gives us the value of y in terms of x, to substitute for y in the first equation. Then we end up with an equation with a unique unknown, for which we can solve:

$x+y=-2\\x+(2x+10)=-2\\x+2x+10=-2\\3x+10=-2\\3x=-2-10\\3x=-12\\x=\frac{-12}{3} \\x=-4$

Next we use this value we obtained for x (-4) in the same equation we use for substitution in order to find which y value corresponds to this:

$y=2x+10\\y=2(-4)+10\\y=-8+10\\y=2$

Then we have the pair (x,y) that satisfies both equations (-4,2), which is therefore the point on the plane where both lines intercept.

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2 years ago