Question

0.18(5x − 4) = 0.5x + 0.8

Answer 1

$\begin{array}{l}\\ \text{We have:}\\ 0.18(5x-4)=0.5x+0.8\\ \Rightarrow 100\times 0.18(5x-4)=100(0.5x+0.8)\left(\mathrm{M}\text{ultipling both sides by 100}\right)\\ \Rightarrow 18(5x-4)=100\times 0.5x+100\times 0.8\\ \Rightarrow 90x-72=50x+80\\ \Rightarrow 90x-50x=80+72\\ \Rightarrow 40x=152\\ \Rightarrow x=\frac{152}{40}\\ \Rightarrow \text{x=}\frac{19}{5}\text{=3.8}\\ \\ \text{CHECK: Substituting}x\text{=}3.8\text{in the given equation, we get:}\\ \\ \text{LHS=}0.18(5x-4)\\ \text{=}0.18(5\times 3.8-4)\\ \text{=0}\text{.18}\times \text{15}\\ \text{=2}\text{.7}\\ \\ \text{RHS=}0.5x+0.8\\ =0.5\times 3.8+0.8\\ =1.9+0.8\\ =2.7\\ \text{∴ LHS=RHS}\\ \text{Hence,}x\text{=}3.8\text{is a solution of the given equation}\text{.}\\ \text{Verified.}\end{array}$