Please help me if you can! ​

A is 55°

Step-by-step explanation:

To solve this, you need to remember that the sum of the angles inside a triangle is equal to 180 degrees.

Also, noting that this is an isosceles triangle.  That means that a and b are equal.  With that in mind, we can simply say:

a + b + c = 180

a ≡ b ∴ 2b + c = 180

2(4x + 31)° + (2x + 58)° = 180°

8x° + 62° + 2x° + 58° = 180°

Let's just stop right here, and note that normally you can treat symbols of measurements just like variables.  We've done the same here, applying the distributive property with the ° symbol.  Note though that it's currently part of every single term, so I'm going to factor it out:

(8x° + 62° + 2x° + 58°) / 1° = 180° / 1°

8x + 62 + 2x + 58 = 180

10x + 120 = 180

10x = 60

x = 6

Again noting that A and B are identical due to this being an Isosceles triangle, we can say:

A = (4x + 31)°

A = 24° + 31°

A = 55°

We can also check our answer.  The sum of the angles should be 180, and two of those angles should be 55.  That means that angle C should be 180 - 2 * 55, or 180 - 110 = 70.  Let's test it:

70 = 2x + 58

70 = 12 + 58

70 = 70

So we know that our answer is correct.