Question

x2-10x+21=0 Next class solve the equation

Answer 1

Answer:

${x}^{2} - 10x + 21 = 0 \\ \\ {x}^{2} - 3x - 7x + 21 = 0 \\ \\ ( {x}^{2} - 3x) - (7x + 21) = 0 \\ \\ x(x - 3) - 7(x - 3) = 0 \\ \\ (x - 3)(x - 7) = 0 \\ \\ x - 3 = 0 \: or \: x - 7 = 0 \\ \\ x = 3 \: or \: x = 7$

Answer 2

$\large\red{\text\:Answer}$

$\boxed{ x = 7} \: \: or \: \: \boxed{ x = 3}$ are the roots of the given quadratic equation.

$\large\pink{\text\:Explanation}$

${x}^{2} - 10x + 21 = 0 \\ \\ \implies \: {x}^{2} - 7x - 3x + 21 = 0 \\ \\ \implies \:x(x - 7) \: - 3(x - 7) = 0 \\ \\ \implies \: (x - 7) \: (x - 3) = 0 \\ \\ \implies \: x - 7 = 0 \: \: or \: \: x - 3 = 0 \\ \\ \implies \: \boxed{ x = 7} \: \: or \: \: \boxed{ x = 3}$