Determine which expression is equivalent to 6a + 21. (5 points) a 3(2a + 7) b 3(3a + 18) c 3(a + 7) d 3(3a + 7)

a

Step-by-step explanation:

Given

6a + 21 ← factor out 3 from each term

= 3(2a + 7)

sum of all angle = 180

given angle = 3X, 4 X AND 5 X

3 X + 4 X+ 5 X = 180

12 X = 180

X = 180/ 12

X = 15

X= 15 IS apply to given angle.

3 X= 3 ×15 = 45

4 X= 4 ×15 = 60

5 X = 5 ×15 =75

ANS; The smallest angle is 45

Step-by-step explanation: