Answer:
x = ±√11 +2
Step-by-step explanation:
Given in the question an equation,
x²- 4x - 7 = 0
Step 1
take 7 to the right side of equation
x²- 4x = 7
Step 2
To create a trinomial square on the left side of the equation, find a value that is equal to the square of half of b, the coefficient of x
2ab = -4x
2xb = -4x
b = -2
Step 3
Take square of b and add it to each side of the equation.
x²- 4x + (-2)²= 7 + (-2)²
x²- 4x + 4 = 7 + 4
x²- 4x + 4 = 11
Step 4
Factor the perfect trinomial square
(x−2)² = 11
Step 5
take square root on both sides
√(x−2)² = √11
(x-2) = ±√11
x = ±√11 +2
