All categories

3 years ago

Solve the equation: [3 2 5 5] [x1 x2]+ [1 2]= [2 -3]

Mathematics

1 answer:

dsp733 years ago

7 0

9514 1404 393

Answer:

(x1, x2) = (3, -4)

Step-by-step explanation:

As with any 2-step linear equation, subtract the constant, then multiply by the inverse of the coefficient of the variable.

$\left[\begin{array}{cc}3&2\\5&5\end{array}\right]\left[\begin{array}{c}x\\y\end{array}\right]+\left[\begin{array}{c}1\\2\end{array}\right]=\left[\begin{array}{c}2\\-3\end{array}\right]\\\\\left[\begin{array}{cc}3&2\\5&5\end{array}\right]\left[\begin{array}{c}x\\y\end{array}\right]=\left[\begin{array}{c}1\\-5\end{array}\right]\\\\\left[\begin{array}{c}x\\y\end{array}\right]=\dfrac{1}{5}\left[\begin{array}{cc}5&-2\\-5&3\end{array}\right]\left[\begin{array}{c}1\\-5\end{array}\right]$

Performing the multiplication of the matrix by the vector gives the solution.

x = ((5)(1) +(-2)(-5))/5 = 15/5 = 3

y = ((-5)(1) +(3)(-5))/5 = -20/5 = -4

Using your variables, x1, x2, the solution is ...

(x1, x2) = (3, -4)

You might be interested in

Which inequality is represented by the graph? y≥35x−1.5 y≤35x−1.5 y<35x−1.5 y>35x−1.5

Setler79 [48]

Answer:

y > 0.6x - 1.5

Step-by-step Explanation:

We need two points, to get to the equation of the graph.

Since we've got the following equation for two points (x1, y1), (x2, y2):-

$\boxed{ \mathsf{ \red{y - y_{1} = \frac{y_{2} - y_{1}}{x_{2} - x_{1}} (x - x_{1}) }}}$

okay soo

I found two points that lie on this graph, not on the shaded region but yeah the dotted line which defines the graph.

one point is <u>(0, -1.5)</u> which lies on the y axis(the point where the dotted line touches the y axis)

other point is <u>(2.5, 0)</u> and this lies on the x axis

placing these points in the place of (x1, y1) and (x2, y2) in the above mentioned equation

$\mathsf{\implies y - ( - 1.5) = \frac{0 -( - 1.5)}{2.5 -0 } (x -0 )}$

you can take any one as (x1, y1) or (x2, y2).

so upon solving the above equation we get

$\mathsf{\implies (y + 1.5) = \frac{0 + 1.5}{2.5 } (x )}$

$\mathsf{\implies y + 1.5 = \frac{ 1.5}{2.5 } x }$

$\mathsf{\implies y + 1.5 = \frac{ \cancel{1.5}\:\:{}^3}{\cancel{2.5}\:\:{}^5 } x }$

$\mathsf{\implies y + 1.5 = \frac{ 3}{5 } x }$

multiplying both sides by 5

$\mathsf{5y + 7.5 = 3x}$

okay so this is the required equation of the dotted line

now we'll find the inequality

for this check whether the origin (0,0) lies under the shaded region or not

in this case it does

replacing x and y with 0

$\mathsf{\implies5(0) + 7.5 = 3(0)}$

$\mathsf{\implies0 + 7.5 = 0}$

this is absurd, 7.5 is not equal to 0 so we're gonna replace that equals sign with that of inequality

7.5 is greater than 0! so,

$\mathsf{\implies7.5 > 0}$

this goes for the whole equation, since we didnt swap any thing from left to right side of the equation or vice versa we can use this sign, to obtain the required inequality

$\mathsf{5y + 7.5 > 3x}$