Question

What's the answer on x^2 = 11x - 28??

Answer 1

x^2-11x+28=0
x^2-4x-7x+28=0
x(x-4)-7(x-4)=0
(x-7)(x-4)=0

therefore x=7 or4

Answer 2

x^2 = 11x - 28 , in this two solutions can be found, x = 7 and x = 4
Method:
First, by rearranging the equation by subtracting what is to the right of the equal sign from both sides of the equarion:
x^2 - 11*x - (-28) = 0

STEP BY STEP SOLUTION:

Factoring x^2 - 11x + 28
The first you see is, x^2 it's coefficient is 1.
The middle term is, - 11x it's coefficient is - 11.
The last term, "the constant", is + 28.

Step-1: Multiply the coefficient of the first term by the constant, that is,
1 × 28 = 28

Step-2: Find two factors of 28 whose sum equal the coefficient number of the middle term, which should - 11.

- 28 + -1 = -29
- 14 + -2 = -16
- 7 + - 4 = -11 That's it!!

Step-3: Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, - 7 and - 4.

x^2 - 7x - 4x - 28

Step-4: Add up the first 2 terms, pulling out like factors:

x × (x - 7)

Add up the last two terms, pulling out common factors:

4 × (x - 7)

Step-5: Add up the four terms of step 4:

(x - 4) × (x - 7)

WHICH IS THE DESIRED FACTORISATION.