a. \( x+-6+5 x+3 x^{2}-1= \)

Let’s simplify that expression! We have \( x - 6 + 5x + 3x^2 - 1 \). First, combine like terms: the \(x\) terms are \(x + 5x = 6x\), and then the constants: \(-6 - 1 = -7\). So, we can rewrite it as \(3x^2 + 6x - 7\). Voilà! Now, you’ve got a quadratic equation, which opens the door to various methods for solving it, like factoring, completing the square, or using the quadratic formula. Quadratics actually pop up everywhere, from projectile motion to financial calculations, making them super practical to master!