Question

X² - 49 = 0. A B C X' X''

Answer 1

Resposta:

+-7

Explicação passo-a-passo:

X² - 49 = 0

X² =49

X=+-√49

x=+-7

Answer 2

$\mathtt{{x}^{2}-49=0}\\\mathtt{{x}^{2}=49}\\\mathtt{x=\pm\sqrt{49}}\\\mathtt{x=\pm7}$

Outro modo:

a=1

b=0

c=-49

$\mathtt{\Delta={b}^{2}-4ac}$

$\mathtt{\Delta={0}^{2}-4.1.(-49)}$

$\mathtt{\Delta=196}$

$\mathtt{x=\dfrac{-b\pm\sqrt{\Delta}}{2a}}$

$\mathtt{x=\dfrac{0\pm\sqrt{196}}{2.1}}$

$\mathtt{x=\dfrac{0\pm14}{2}}\\\mathtt{x_{1}=\dfrac{0+14}{2}=\dfrac{14}{2}=7}\\\mathtt{x_{2}=\dfrac{0-14}{2}=-\dfrac{14}{2}=-7}$

$\boxed{\boxed{\mathtt{s=\{-7,7\}}}}$