X² + 4x - 21 = 0 answer and solution? please help me

x = -7, 3

General Formulas and Concepts:

Order of Operations: BPEMDAS

Standard Form: ax² + bx + c = 0

Factoring

Step-by-step explanation:

Step 1: Define

x² + 4x - 21 = 0

Step 2: Solve for x

Factor:                         (x - 3)(x + 7) = 0Find roots:                   x = -7, 3

Step 3: Check

Plug in x to verify it's a solution.

Substitute:                        (-7)² + 4(-7) - 21 = 0Exponents:                       49 + 4(-7) - 21 = 0Multiply:                            49 - 28 - 21 = 0Combine like terms:        0 = 0Substitute:                        (3)² + 4(3) - 21 = 0Exponents:                       9 + 4(3) - 21 = 0Multiply:                            9 + 12 - 21 = 0Combine like terms:        0 = 0

x = - 7 or x = 3

Step-by-step explanation:

x² + 4x - 21 = 0

Using the quadratic formula which is

From the question

a = 1 , b = 4 , c = - 21

We have

So we have

We have the final answer as

x = - 7 or x = 3

Hope this helps you

y=1

Step-by-step explanation:

substitute values

substitute 2 instead of x which becomes 4

then subtract 4 from 5 which becomes 1

so y is 1