You need to find the value of a so solve the first equation in terms of x:

3a + x = 2
x = 2 - 3a

then substitute the result (2 - 3a) into the second equation:

-9a + 6(2 - 3a) = -2
-9a + (6 x 2) + (6 x -3a) = -2
-9a + 12 - 18a = -2
-9a - 18a = -2 - 12
-27a = -14
a = \( \frac{-14}{-27} \)
a = \(\frac{14}{27}\)

To factor a quadratic expression, apply the FOIL (First, Outside, Inside, Last) method in reverse.

The Pythagorean theorem defines the relationship between the side lengths of a right triangle. The length of the hypotenuse squared (c²) is equal to the sum of the two perpendicular sides squared (a² + b²): c² = a² + b² or, solved for c, \(c = \sqrt{a + b}\)

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

7a + 3a = 10a

The coordinate grid is composed of a horizontal x-axis and a vertical y-axis. The center of the grid, where the x-axis and y-axis meet, is called the origin.