Find x. Give reasons to justify your solution. b Lines AB and CD are straight lines.

x is 28

Step-by-step explanation:

When two lines intersected in a point, then they formed two pairs of vertically opposite angles. The vertically opposite angles are equal in measures

Let us solve our question

∵ AB and CD are straight lines intersected at O

∴ ∠AOC and ∠DOB are vertically opposite angles

∴ ∠AOD and ∠COB are vertically opposite angles

→ The vertically opposite angles are equal in measures

∴ m∠AOC = m∠DOB

∴ m∠COB = m∠AOD

→ ∠ COB is formed from ∠COE, ∠EOF, and ∠FOB

∵ m∠COB = m∠COE + m∠EOF + m∠FOB

∵ m∠COE = 3x, m∠EOF = x, m∠FOB = x + 12

∴ m∠COB = 3x + x + x + 12

→ Add the like terms

∴ m∠COB = 5x + 12

∵ m∠AOD = 152°

∵  m∠COB = m∠AOD

∴ 5x + 12 = 152

→ Subtract 12 from both sides

∴ 5x + 12 - 12 = 152 - 12

∴ 5x = 140

→ Divide both sides by 5

∴

∴ x = 28

→ To justify the solution substitute x by 28 in m∠COB the answer must

   be 152°

∵ m∠COB = 5x + 12

∵ x = 28

∴ m∠COB = 5(28) + 12

∴ m∠COB = 140 + 12

∴ m∠COB = 152°

∴ The value of x is correct

f(x) = - 2/3x + 5; f(5/2)

substitute 5/2 in for x:

f(5/2) = -2/3(5/2) + 5

simplify the right side:

f(5/2) = -5/3 + 5

f(5/2) = 10/3

answer:

f(5/2) = 10/3

i hope this you!

fist on the left goes with the third on the right. second on the left goes with the fourth on the right. third on the left goes with the second on the right. the fourth on the left goes with first on the right