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Apr 13, 2024
 #1
avatar+921 
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We can solve this system of equations by adding and subtracting the equations strategically to eliminate one of the variables.

Adding the Equations:

Adding the two given equations eliminates the term ab^2:

(a^3 + 3ab^2) + (3a^3 - ab^2) = 679 + 615

Combine like terms:

4a^3 = 1294

Solving for a^3:

Divide both sides by 4:

a^3 = 1294 / 4 = 323.5

Subtracting the Equations:

Subtracting the second equation from the first equation eliminates the term 3a^3:

(a^3 + 3ab^2) - (3a^3 - ab^2) = 679 - 615

Combine like terms:

4ab^2 = 64

Solving for ab^2:

Divide both sides by 4:

ab^2 = 16

Relating a and b:

Since we know both a^3 and ab^2, we can try to express one variable in terms of the other.

From the equation for a^3, we can write a =∛(323.5).

Relating a - b:

We want to find a - b. Since we don't have a direct equation for b, we can try to manipulate the equation for ab^2.

Rewrite the equation for ab^2:

b^2 = a(ab^2) = a * 16

Substitute a = ∛(323.5):

b^2 = ∛(323.5) * 16

Now, we can express b in terms of a:

b = ± 4 * ∛(323.5)

Finding a - b:

Since a and b are real numbers, we can consider both positive and negative values of b. However, we only care about the difference a - b.

There are two cases:

Case 1: b = 4 * ∛(323.5)

a - b = ∛(323.5) - (4 * ∛(323.5))

Factor out ∛(323.5):

a - b = ∛(323.5) (1 - 4)

a - b = -3 * ∛(323.5)

Case 2: b = -4 * ∛(323.5)

a - b = ∛(323.5) - (-4 * ∛(323.5))

Factor out ∛(323.5):

a - b = ∛(323.5) (1 + 4)

a - b = 5 * ∛(323.5)

Conclusion:

Since we don't know the signs of a and b beforehand, both cases are valid. Therefore, a - b can be either -3 * ∛(323.5) or 5 * ∛(323.5).

Both answers are negative and positive multiples of the same cube root, so they essentially represent the same value with opposite signs. The absolute value of a - b is:

|a - b| = |(-3) * ∛(323.5)| = |5 * ∛(323.5)| = 5 * ∛(323.5)

Apr 13, 2024
 #1
avatar+921 
-1

We can solve this problem by recognizing that subdividing a triangle into smaller similar triangles reduces the area by a factor based on the ratio of side lengths.

 

Similarity of Triangles:

 

Since M, N, and O are midpoints of sides, segments NO, OM, and MN are parallel to sides KL, LJ, and JK respectively (corresponding sides theorem).

 

Due to alternate interior angles, angles in triangles JKL, JMN, JNO, etc. are congruent (alternate interior angles theorem).

 

Therefore, triangles JKL, JMN, JNO, etc. are similar by Angle-Angle (AA) Similarity.

 

Ratio of Side Lengths:

 

Since M, N, and O are midpoints, segments NO, OM, MN, PN, QM, and PR are all half the length of their corresponding sides in the larger triangle (JKL).

 

Area Ratio of Similar Triangles:

 

The ratio of the areas of two similar triangles is equal to the square of the ratio of their corresponding side lengths.

 

Let k be the scaling factor between triangles JKL and PQR (i.e., the ratio of side lengths between corresponding sides).

 

The area of triangle PQR is 12.

 

Relating Areas of JKL and PQR:

 

Area(PQR) / Area(JKL) = k^2 (ratio of areas of similar triangles)

 

Substitute the given value:

 

12 / Area(JKL) = k^2

 

Relating Side Lengths:

 

Since PN, QM, and PR are half the length of their corresponding sides in JKL, k = 1/2 (ratio of side lengths).

 

Finding Area(JKL):

 

Substitute k = 1/2 in the equation from step 4:

 

12 / Area(JKL) = (1/2)^2

 

Multiply both sides by Area(JKL):

 

12 = Area(JKL) / 4

 

Solve for Area(JKL):

 

Area(JKL) = 12 * 4 = 48

 

Therefore, the area of triangle JKL is 48 square units.

Apr 13, 2024
 #1
avatar+921 
-1

Angles in Triangle STU:

 

We are given that angle TSU = 62 degrees and angle STU = 29 degrees. Since the angles in a triangle add up to 180 degrees, we can find the third angle (angle SUT):

 

angle SUT = 180 degrees - angle TSU - angle STU = 180 degrees - 62 degrees - 29 degrees = 89 degrees.

 

Angles in Triangles MNU and MNP:

 

Since M, N, and P are midpoints of sides, segments MN, NP, and PM are parallel to TU, US, and ST respectively (corresponding sides theorem).

 

Due to alternate interior angles, angle MNU = angle TSU = 62 degrees and angle MNP = angle STU = 29 degrees (alternate interior angles theorem).

 

Angle NZM and Angle NPM:

 

Triangle NUZ is a right triangle (angle NUZ = 90 degrees) since UZ is an altitude.

 

Since M is the midpoint of TU, segment NZ is half of segment TU. Similarly, segment NP is half of segment US.

 

Therefore, triangles NUZ and MNP are similar (AA Similarity).

 

Corresponding angles in similar triangles are congruent. Thus, angle NZM = angle NMP (corresponding angles).

 

Finding Angle NZM + Angle NPM:

 

We know angle MNU = 62 degrees and angle NMP = angle NZM (from step 3). Since angles in triangle MNU add up to 180 degrees:

 

angle NZM + angle NMP + angle MNU = 180 degrees

 

Substitute the known values:

 

angle NZM + angle NZM + 62 degrees = 180 degrees

 

Combine like terms:

 

2 * angle NZM = 180 degrees - 62 degrees

 

Solve for angle NZM:

 

angle NZM = 118 degrees / 2 = 59 degrees

 

Therefore, angle NZM + angle NPM = angle NZM + angle NZM (since they are congruent) = 59 degrees + 59 degrees = 118 degrees.

Apr 13, 2024

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