Question

Determine o valor das incognitas das seguintes equações: d) 9x - 20 = 8(x - 1) e) 4(x -2) = 4 + 2(x -1) f) 10(x -1) -7(x + 1) = 4 g) 2(1,6 + x) + 0,5(1 + x) = 4,2 h) 3(1,4 - x) + 5x = - (x - 4,8) i) 5(2x + 7) -1 = 4(x - 5) = + 9 j) 2(x + 1) + 5(x-1) = 7

Answer 1

d) 9x-20=8(x-1)

    9x-20=8x-8

   x=12

e) 4(x-2)=4+2(x-1)

4x-8=4+2x-2

4x-2x=4-2+8

2x=10

f) 10(x-1)-7(x+1)=4

10x-10-7x-7=4

10x-7x=4+7+10

3x=21

x=21/3

x=7

g) 2(1,6+x)+0,5(1+x)=4,2

3,2+2x+0,5+0,5x+4,2

2x+0,5+4,2-3,2-0,5

2,5x=0,5

x=0,5/2,5

x=0,2

h) 3(1,4+x)+5x=-(x-4,8)

4,2-3x+5x=-x+4,8

-3x+5x+x=4,8-4,2

2x+x=0,6

3x=0,6

x=0,6/3

x=0,2

i) 5(2x+7)-1=4(x-5)+9

10x+35-1=4x-20+9

10x-4x=-20+9-35

10x-4x=-11-35

6x=-46

x=-46/6

x=-7,6

j) 2(x+1)+5(x-1)=7

2x+2+5x-5=7

2x+5x=7+5-2

7x=12-2

7x=10

x=10/7

x=1,43