I am confused about question. Don't we have to find roots? we won't apply quadratic equation formula?
GreenlightTestPrep wrote:
The question asks us to find the value of x² + 3x - 4
Notice that this in a algebraic EXPRESSION and not an algebraic EQUATION.
Most algebraic EXPRESSIONS can have infinitely many values.
For example, if x = 0, then x² + 3x - 4 = 0² + 3(0) - 4 = -4
If x = 2, then x² + 3x - 4 = 2² + 3(2) - 4 = 6
If x = 10, then x² + 3x - 4 = 10² + 3(10) - 4 = 126
If x = -5, then x² + 3x - 4 = (-5)² + 3(-5) - 4 = 6
etc
So, on it's own, the algebraic EXPRESSION x² + 3x - 4 has no particular value. In fact, the value of x² + 3x - 4 depends exclusively on the value of x.
The EQUATION x² + 3x - 4 = 0 is different.
When we're asked to solve this equation, we're looking for a value(s) of x such that the algebraic EXPRESSION x² + 3x - 4 has the value of 0.
Cheers,
Brent