MARKING AS BRAINLIEST!! (Geometry)

x = 15.49

Step-by-step explanation:

As you can see this is a right-angled triangle due to the right angle symbol, we can use Pythagorean theory to find the unknown length:

In this case, we know C and B but not A so:

Now plug the values in:

Square root the answer to get A:

a = 15.49

x = 15.49

Hope this helps!

x² + 3x + 7 = 0       [ax² + bx + c]

a = 1

b = 3

c = 7

quadratic formula:

    (+/- is this ±)

plug in the numbers into the variables

your answer is a