me ajudem a resolver?
a) x(x+11)+2(x+21)=0
b) 6(x²-1)-x=14+5x²
a) x²+11x+2x+42=0
x²+13x+42=0
a=1
b=13
c=42
delta = b² - 4ac
delta = 13² - 4 (1)(42)
delta = 169 -168
delta = 1
x = -b +/- raiz de delta = -13 +/- raiz de 1 = -13 +/- 1
2a 2.1 2
x' = -13-1 = -14 = -7
2 2
x'' = -13+1 = -12 = -6
2 2
S={-7,-6}
b)6x²-6-x=14+5x²
6x²-5x²-6-14-x=0
x²-x-20=0
a=1
b= -1
c= -20
delta= b² - 4ac
delta = (-1)² - 4(1)(-20)
delta = 1 + 80
delta = 81
x= -b +/- raiz de delta
2a
x= -(-1) +/- raiz de 81 = 1 +/- 9
2.1 2
x' = 1+9 = 10 = 5
2 2
x'' = 1-9 = -8 = -4
2 2
S={5,-4}
a) x(x+11)+2(x+21)=0
x^2 + 11x + 2x + 42 = 0
x^2 + 13x + 42 = 0
delta=13^2 - 4.1.42= 169-168= 1
x=-13+/- 1 ==> x1= -13+1 ==>x1= - 6 ; x2= -13-1 ==> x2 = - 7
2.1 2 2
b) 6(x²-1)-x=14+5x²
6x²- 6 - x -14 + 5x² = 0
x² - x - 20 = 0
delta= (-1)^2 -4.1.(-20) = 1 +80 = 81
x= 1+/- 81 ==>x=1+/- 9 ==>x1=1+9 = 5 ; x2= 1-9 = -4
2.1 2 2 2
