Question

What method would you choose to solve the equation 2x2 – 7 = 9? Explain why you chose this method.

Answer 1

Normal solution;
By taking -7 to the RHS, you will have

`2 x^(2) =16`
dividing both sides by 2 gives;

`x^(2) =8 x= √(8) x=2 √(2)`

Answer 2

This is a quadratic equation . We order to equate to zero

2x² – 7 = 9

2x² - 7-9 = 0
2x² - 16 = 0

This equation is a binomial
2* (x² - 8) = 0
We choose the simplest method . The equation with practice it can be calculated in the memory

The product is equal to 0 if one of the factors is zero

2≠0 ∨ x² - 8 = 0
x² = √8
x = √8 ∨ x= - √8

Answer : x = √8 ∨ x = -√8