Question

calcule as raízes das equações
(a) x²- 36 = 0

(b)x²+ 7x=0

(c)2x² -72 = 0

(d)2x² - 8x =0

Answer 1

Explicação passo-a-passo:

a) x²-36=0

x²=36

x= +- raiz de 36

x= +-6

x¹= +6 S={ 6,-6} /\>0 => 2 raízes

x²= -6

b) x²+7x=0 a=1

b=7

c=0

/\=b²-4ac x= -b+- raiz de delta/2

/\=(7)²-4×1×0 x= -(7)+-raiz de 49 /2

/\=49-0 x= -7+-7 /2

/\=49

x¹=-7+7/2 => x¹=0/2 => x¹=0

x²= -7-7/2 => x²= -14/2 => x²= -7

/\=0 => raiz nula

c) 2x²-72=0

a=2 /\=b²-4ac

b=-72 /\=(-72)²-4×2×0

c=0 /\=5184

x= -b+- raiz de delta/2a

x= -(-72)+-72/2×2

x= 72+-72/4

x¹=72+72/4 => x¹= 144/4 => x¹= 36

x²= 72-72/4 => x²=0/4 => x²=0

S={ 36,0}

d)2x²-8x=0

a=2 /\=b²-4ac

b=-8 /\=(-8)²-4ac

c=0 /\=64-4×2×0

/\= 64

x= -b+- raiz de delta /2a

x= -(-8) +- 8 /2×2

x= 8 +-8/4

x¹= 8+8/4 => x¹=16/4 => x¹=4

x²=8-8/4 => x²=0

S={4,0}

Espero ter ajudado!