Answer:
[tex]x=9[/tex]
Step-by-step explanation:
ABC is the sum of the angles CBD and ABD. So:
[tex]\angle ABC=\angle CBD+\angle ABD[/tex]
Substitute them for their equations:
[tex](-7x+241)=(-4x+123)+(154-7x)[/tex]
Solve for x. Combine like terms on the right:
[tex]-7x+241=-11x+277[/tex]
Add 11x to both sides:
[tex]4x+241=277[/tex]
Subtract 241 from both sides:
[tex]4x=36[/tex]
Divide both sides by 4:
[tex]x=9[/tex]
The value of x is 9.
And we're done!
