If f(x) = -(-2x - 5), what is f(-5)?
2 answers:
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Answer:
m∠BCD = 90°
∠BCD is a right angle
Step-by-step explanation:
<em>If a ray bisects an angle, that means it divides the angle into two equal parts in measure</em>
∵ Ray CE bisects ∠BCD
→ Means divide it into two angles BCE and ECD which equal in measures
∴ m∠BCE = m∠ECD = m∠BCD
∵ m∠BCE = 3x - 6
∵ m∠ECD = 2x + 11
→ Equate them to find x
∴ 3x - 6 = 2x + 11
→ Add 6 to both sides
∵ 3x - 6 + 6 = 2x + 11 + 6
∴ 3x = 2x + 17
→ Subtract 2x from both sides
∵ 3x - 2x = 2x - 2x + 17
∴ x = 17
∵ m∠BCE = m∠BCD
→ Substitute x in the measure of ∠BCE to find it, then use it to
find m∠BCD
∵ m∠BCE = 3(17) - 6 = 51 - 6
∴ m∠BCE = 45°
∵ 45 = m∠BCD
→ Multiply both sides by 2
∴ 90 = m∠BCD
∴ m∠BCD = 90°
→ The measure of the acute angle is less than 90°, the measure of
the obtuse angle is greater than 90°, and the measure of the
right angle is 90°
∴ ∠BCD is a right angle