Question

500(1+x)(x+8％)=168,

Answer 1

500(1+x)(x+8℅)=168

5(1+x)(100x+8)=168

5(1+x)(25x+2)=42

5(25x+2+25x²+2x)=42

125x²+135x+10=42

125x²+135x=32

x²+1.08x=0.256

x²+1.08x+0.54²=0.256+0.54²

(x+0.54)²=0.5476

x+0.54=±0.74

x+0.54=0.74或x+0.54=-0.74

x1=0.2,x2=-1.28