Question

$x { }^{2} + x - 20 = 0$
what is the answer?​

Answer 1

Answer:

Given :-

➜ x² + x - 20 = 0

Solution :-

➜ x² + x - 20 = 0

➞ x² + (5 - 4)x - 20 = 0

➞ x² + 5x - 4x - 20 = 0

➞ x(x + 5) - 4(x + 5) = 0

➞ (x + 5) (x - 4) = 0

➞ (x + 5) = 0

➞ x + 5 = 0

➞ x = - 5

Either,

➞ (x - 4) = 0

➞ x - 4 = 0

➞ x = 4

∴ The answer of this question is x = - 5, 4

Answer 2

$sum = 5 + ( - 4) = 1\\ product = 5 \times - 4 = - 20$

${x}^{2} + 5x - 4x - 20 = 0\\ x(x + 5) \: \: \: - 4(x + 5) = 0 \\ (x - 4) \: \: \: (x + 5) \\ x - 4 = 0 \\ x = 4 \\ x + 5 = 0$

$x = - 5 \\ 4 \: and \: - 5 \: \: are \: the \: roots \: of \: the \: \\ given \: quadratic \: equation$