Question 991894
<pre>
I assume you mean that those three angles are angles of
a triangle,

Since the sum of the three angles of any triangle is 180°,

We indicate their sum and set it equal to 180°

(x+64°)+(x+84°)+40° = 180°

Solve that and get x = -4°

Then use that value of x to find angle A.  We can't help
you any further because we don't know what angle is
represented by A.

Edwin</pre>