Answer:
x = 3,7
Step-by-step explanation:
x² - 10x + 21 = 0
x² - 7x - 3x + 21 = 0
x(x - 7) - 3(x - 7) = 0
(x - 3)(x - 7) = 0
x = 3, 7
Means the graph cuts the x-axis at 3 and 7
Answer:
x = 3, x = 7
Step-by-step explanation:
Assuming you require the solution to this quadratic equation.
Given
x² - 10x + 21 = 0
Consider the factors of the constant term (+ 21) which sum to give the coefficient of the x- term (- 10)
The factors are - 7 and - 3, since
- 7 × - 3 = 21 and - 7 - 3 = - 10, thus
x² - 10x + 21 = 0 ← in standard form
(x - 7)(x - 3) = 0 ← in factored form
Equate each factor to zero and solve for x
x - 3 = 0 ⇒ x = 3
x - 7 = 0 ⇒ x = 7
