Question

The difference of the square of a number and 28 is equal to 3 times that number

Answer 1

Answer:

- 4, 7

Step-by-step explanation:

Let the required number be x.

Therefore, according to the given condition:

${x}^{2} - 28 = 3x \\ {x}^{2} - 3x - 28 = 0 \\ {x}^{2} - 7x + 4x - 28 = 0 \\ x(x - 7) + 4(x - 7) = 0 \\ (x - 7)(x + 4) = 0 \\ x - 7 = 0 \: or \: x + 4 = 0 \\ x = 7 \: or \: x = - 4$