Q. Find the solutions of the quadratic equation 2x2−8x−9=0.Choose 1 answer:(A) 2±234i(B) −2±234i(C) 2±234(D) 1±434
Identify coefficients: Identify the coefficients of the quadratic equation 2x2−8x−9=0.The standard form of a quadratic equation is ax2+bx+c=0. Here, a=2, b=−8, and c=−9.
Use quadratic formula: Use the quadratic formula to solve for x. The quadratic formula is x=2a−b±b2−4ac.
Calculate discriminant: Calculate the discriminant D=b2−4ac.D=(−8)2−4(2)(−9)D=64+72D=136The discriminant is positive, which means there are two real and distinct solutions.
Substitute values into formula: Substitute the values of a, b, and D into the quadratic formula.x=2⋅2−(−8)±136x=48±136
Simplify square root: Simplify the square root of the discriminant. 136 can be simplified to 4×34, which is 2×34.
Substitute simplified square root: Substitute the simplified square root back into the equation. x=48±2⋅34
Simplify equation: Simplify the equation by dividing both terms in the numerator by 4.x=48±42⋅34x=2±234
Write final solutions: Write the final solutions.The solutions are x=2+(234) and x=2−(234).