The missing symbol is an equal sign
Standard form: ax^2 + bx + c = y
Steps to simplify:
2x^2 - 1 = 3x + 4
~Subtract (3x + 4) to both sides
2x^2 - 1 - 3x + 4 = 3x + 4 - 3x + 4
~Simplify
2x^2 - 3x - 5 = 0
(a = 2, b = -3, c = -5)
Now that we know what these values are, we can use the quadratic formula to solve.

Answer: x = 5/2 or x = -1
Best of Luck!
Answer:
x=27
Step-by-step explanation:
The sum of the angles of a triangle is 180 degrees
90 + x+23 + x+13 = 180
Combine like terms
126 +2x = 180
Subtract 126 from each side
126-126 +2x=180-126
2x =54
Divide by 2
2x/2 = 54/2
x = 27
The variable cc refers to how much ink is in a certain number of
cartridges. If the box says 42cc, that means the amount of ink in those
particular cartridges is 42. If a box said 12cc, the amount would be 12.
The variable cc just states the amount of ink you can expect from a
particular amount of cartridges.