The three planes given meet at a point. The planes are 3x+y-2z = 11, 4x-2y+z = -5, x+5y-4z = 33. The intersection is at what point? (Please explain.)

(2, 7, 1)

Step-by-step explanation:

We have three equations, and using Gauss-Jordan Elimination, we can solve for x, y, and z

3x + y - 2z = 11

4x - 2y + z = -5

x + 5y - 4z = 33

We can start by taking out the z from all rows except one. To do this, we can work with the second row. I chose the second row because -5 is small and easy to add up with other numbers, and z has no coefficient in this row.

We can add 2 times the second row to the first row and 4 times the second row to the third row to get

11x - 3y = 1

4x - 2y + z = -5

17x -3y = 13

We then have the first and third rows having two variables. Since the y coefficients are the same, we can eliminate the y by adding the negative of the first row to the third row. Our result is then

11x - 3y = 1

4x - 2y + z = -5

6x = 12

From the third row, we can gather that x= 2. We can then plug that into the first row to get

22 -3y = 1

subtract 22 from both sides

-3y = -21

divide both sides by -3

y = 7

We can then plug our x and y values into the second row to get

4(2) - 2(7) + z = -5

8 - 14 + z = -5

-6 + z = -5

add 6 to both sides

z = 1

Our answer is thus (2, 7, 1)

step-by-step explanation:

we are given a graph for system of inequalities.

in order to write the system of inequalities for the given graph, we need to find the inequality for each of the line separately.

let us find the slope of dotted line first.

taking two coordinates on the graph.

let us say (0,0) and (3,1).

let us find the slope of the line now.

slope of the dotted line would be =.

y-intercept of dotted line is y=0 only.

plugging slope m= and b=0 in slope-intercept form y=mx+b, we get

.

the line is shaded up of that dotted line.

therefore, for shading up we would take greater than inequality symbol > .

and because it's a dotted line we would take only > symbol in place of = sign in above equation of line.

therefore, inequality for dotted line would be

let us take two points (3,1) and (0,4) on the solid line.

slope of the solid line would be =.

for the solid line we have y-intercept b= 4.

plugging slope m= -1 and b=4 in slope-intercept form y=mx+b, we get

y = -1x + 4.

the line is shaded down of that solid line.

therefore, for shading down we would take less than inequality symbol < .

and because it's a solid line we would take ≤ symbol in place of = sign in above equation of line.

therefore, inequality for solid line would be

-12 > a

step-by-step explanation:

-11 > 1 + a

subtract 1 from each side

-11-1 > 1-1+a

-12 > a