Question

the measure of the exterior angle at B is(6x-7) degrees.Angle CAB is (2x) degrees and angle BCA is (103-x) find for x.

Answer 1

check the picture below.

the interior angle at B is a linear angle with the exterior angle, thus their sum is 180°, so if we subtract 6x - 7 from 180°, what's  leftover is the interior angle at B.

keeping in mind that the sum of all interior angles in a triangle add up to 180°, thus

$\bf \stackrel{A}{(2x)}+\stackrel{B}{[180-(6x-7)]}+\stackrel{C}{(103-x)}=180 \\\\\\ 2x+[187-6x]+103-x=180\implies 2x+187-6x+103-x=180 \\\\\\ -5x=-110\implies x=\cfrac{-110}{-5}\implies x=22$

Answer 2

Answer:

the interior angle at B is a linear angle with the exterior angle, thus their sum is 180°, so if we subtract 6x - 7 from 180°, what's  leftover is the interior angle at B.

Step-by-step explanation: