Expand 8(5-r)/5=-2r as indicated: 40 - 8r
----------- = - 2r
5
Multiply both sides by 5, obtaining 40 - 8r = - 10r
Combine like terms: 40 = - 2r
Divide both sides by -2: -20 = r
The solution to 8(5-r)/5=-2r is -20. Verify this by subbing -20 for r in the given equation.
Find the cube root of 90 if there isn't, try to compare irrational numbers
The length of the altitude AD is 12 units.
<h3>How to find the height of a triangle?</h3>
The height of the triangle can be found as follows:
We have to find an angle using cosine law before we can find the height.
Therefore,
20² = 13² + 21² - 2 × 21 × 13 cos B
400 = 169 + 441 - 546 cos B
400 - 610 = - 546 cos B
-210 = - 546 cos B
cos B = -210 / -546
cos B = 0.38461538461
B = cos⁻¹ 0.38461538461
B = 67.3810899783
B = 67.38°
Hence,
sin 67.38° = opposite / hypotenuse
sin 67.38° = AD / 13
cross multiply
AD = 13 sin 67.38°
AD = 11.9999882145
AD = 12 units
learn more on triangle here: brainly.com/question/13387814
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Answer: induction
Step-by-step explanation:
The greatest common factor is 2