23, Corey bought the mailing tube shown at the right

3x+y=115x-y=21 Directions: Solve each system of equations by elimination. Clearly identify your solution.

olchik [2.2K]

To solve, we will follow the steps below:

3x+y=11 --------------------------(1)

5x-y=21 ------------------------------(2)

since y have the same coefficient, we can eliminate it directly by adding equation (1) and (2)

adding equation (1) and (2) will result;

8x =32

divide both-side of the equation by 8

x = 4

We move on to eliminate x and then solve for y

To eliminate x, we have to make sure the coefficient of the two equations are the same.

We can achieve this by multiplying through equation (1) by 5 and equation (2) by 3

The result will be;

15x + 5y = 55 ----------------------------(3)

15x - 3y =63 --------------------------------(4)

subtract equation (4) from equation(3)

8y = -8

divide both-side of the equation by 8

y = -1

8 0

1 year ago

Two sides of an isosceles triangle measure 3 inches and 7 inches. Which could be the length of the third side?

slamgirl [31]

Answer:

7

Step-by-step explanation:

6 0

3 years ago

Simplify the expression: 6(1 + 2b) =

timama [110]

Answer:

6+12b

Step-by-step explanation:

i took a test with this question and got it right

5 0

3 years ago

Find x so that the points (x,x+1), (x+2,x+3) and (x+3,2x+4) form a right-angled triangle.

azamat

Let a, b, and c be vectors each starting at the origin and terminating at the points (x, x + 1), (x + 2, x + 3), and (x + 3, 2x + 4), respectively.

Then the vectors a - b, a - c, and b - c are vectors that point in directions parallel to each of the legs formed by the triangle with these points as its vertices.

If this triangle is to contain a right angle, then exactly one of these pairs of vectors must be orthogonal. In other words, one of the following must be true:

(a - b) • (a - c) = 0

or

(a - b) • (b - c) = 0

or

(a - c) • (b - c) = 0

We have

a - b = (x, x + 1) - (x + 2, x + 3) = (-2, -2)

a - c = (x, x + 1) - (x + 3, 2x + 4) = (-3, -x - 3)

b - c = (x + 2, x + 3) - (x + 3, 2x + 4) = (-1, -x - 1)

Case 1: If (a - b) • (a - c) = 0, then

(-2, -2) • (-3, -x - 3) = (-2)×(-3) + (-2)×(-x - 3) = 2x + 12 = 0 ==> x = -6

which would make a - c = (-3, 3) and b - c = (-1, 5), and their dot product is not zero. Then the triangles vertices are at the points (-6, -5), (-4, -3), and (-3, -8).

Case 2: If (a - b) • (b - c) = 0, then

(-2, -2) • (-1, -x - 1) = (-2)×(-1) + (-2)×(-x - 1) = 2x + 4 = 0 ==> x = -2

which would make a - c = (-3, -1) and b = (-1, 1), and their dot product is also not zero. The vertices are the points (-2, -1), (0, 1), and (1, 0).

Case 3: If (a - c) • (b - c) = 0, then

(-3, -x - 3) • (-1, -x - 1) = (-3)×(-1) + (-x - 3)×(-x - 1) = x ² + 4x + 6 = 0

but the solutions to x here are non-real, so we throw out this case.

So there are two possible values of x that make a right triangle, x = -6 and x = -2.

3 0

3 years ago

The ratio of the width to the length of a painting is 3 to 7. If the painting is 42 in. long how wide is it

belka [17]

If length is 42 inches, then width is 18 inches.

Step-by-step explanation:

We are given ratio of width to the length of a painting i.e 3 to 7. If the painting is 42 inches long, then how wide it is?

Solving:

$\frac{width}{length}=\frac{width}{length}\\ \frac{3}{7}=\frac{w}{42}\\ Cross\,\,multiply:\\3*42=w*7\\126=w*7\\w=\frac{126}{7}\\w=18$

So, If length is 42 inches, then width is 18 inches.

Keywords: Ratio

Learn more about Ratio at:

#learnwithBrainly

8 0

3 years ago