Question

Alguém pode me ajuda por favor ?

Answer 1

6a) 2x²-72=0
2x²=72
x²=36
x1=+V36  x1=6
x2=-V36  x2=-6
x=[36,-36]
 
b)x²=99-10x²  x²+10x²=99  11x²=99  x²=99/11  x²=9
x=V9
x1=+V9  x1=3
x2=-V9  x2=-3
x=[3,-3]

c)-64+4x²=04x²=64
x²=64/4
x²=16
x=V16
x1=+V16  x1=4
x2=-V16   x2=-4
x=[4,-4]

d)0,15x²=0,6
15/100x²=6/10
x²=6/10]/[15/100]
x²=6/10*100/15
x²=6*100/10*15
x²=600/150
x²=4
x=V4
x1=+V4  x1=2
x2=-V4  x=-2
x=[2,-2]

9a) x²=7x-12
x²-7x-12=0
& = [-7]²-4*1*-12 = 49+48 = 97
x1 = [-(-7)+V97]/2*1 = [7+V97]/2
x2 = [-(-7)-V97]/2*1 = [7-V97]/2
x=[(7+V97)/2, (7-V97)/2]

b) 2x²-3x=2x-1
2x²-3x-2x+1=0  2x²-5x+1=0
& = [-5]²-4*2*1 = 25-8  &=17
x1 = [-(-5)+V17]/2*2 = [5+V17]/4
x2 = [-(-5)-V17]/2*2 = [5-V17]/4
x = ([5+V17]/4, [5-V17]/4)

c) 2x[4x-1]=218x²-2x=21  8x² - 2x - 21=0
& = [-2]²-4*8*-21 = 4 + 672 = 676
x1 = -[-2] +V676 = 2 + 26 = 32
x1 = -[-2] -V676 = 2 - 26 = -24
x = [32, -24]

d) [x-2]²=3x+4
x²-4x+4=3x+4  x²-4x-3x+4-4=0  x² - 7x=0 
x[x-7] = 0
x1 = 0/[x-7]  x1=0
x2-7 = 0/x  x2=7
x= [0, 7]

e) 1-[x+2]²=01-[x²+4x+4]=0  1-x²-4x-4=0  -x²-4x-3=0
& = [-4]²-4*-1*-3 = 16 - 12  &=4
x1 = [-(-4)+V4]/2[-1] = [4+2]/-2 = 6/-2  x1=-3
x2 = [-(-4)-V4]/2[-1] = [4-2]/-2 = 2/-2  x2=-1
x = -3,-1]

f) [3x+1]²+[x-2][x+1]=-1
9x²+6x+1+x²-2=-1  10x²+6x-1+1=0  10x²+6x=0
x[10x+6]=0
x1=0/[10x+6]  x1=0
x2+6=0/x  x2+6=0  x2=-6
x=[0,-6]