Answer:
Step-by-step explanation:
1). 10 = [tex]\frac{1+7x}{7+x}[/tex]
10(7 + x) = 1 + 7x
70 + 10x = 7x + 1
10x - 7x = 1 - 70
3x = -69
x = -23
2). 0.2 = [tex]\frac{6+2x}{12+x}[/tex]
0.2(12 + x) = 6 + 2x
2.4 + 0.2x = 6 + 2x
2.4 - 6 = 2x - 0.2x
1.8x = -3.6
x = -2
3). 0.8 = [tex]\frac{x}{x+0.5}[/tex]
0.8(x + 0.5) = x
0.8x + 0.4 = x
x - 0.8x = 0.4
0.2x = 0.4
x = 2
4). 3.5 = [tex]\frac{4+2x}{0.5-x}[/tex]
3.5(0.5 - x) = 4 + 2x
1.75 - 3.5x = 4 + 2x
-3.5x - 2x = 4 - 1.75
-5.5x = 2.25
x = -[tex]\frac{2.25}{5.5}[/tex]
x = - [tex]\frac{9}{22}[/tex]
