Question Number 175821 by daus last updated on 07/Sep/22
Commented by daus last updated on 07/Sep/22
$${help}\:{me}\:{for}\:{a} \\ $$
Answered by Rasheed.Sindhi last updated on 07/Sep/22
$$\left({a}\right) \\ $$$$\underset{×\mathrm{2}} {\underbrace{\mathrm{5}{x}+\mathrm{3}{y}=\mathrm{4}}}\:\wedge\:\mathrm{2}{y}+\mathrm{4}{z}=\mathrm{5} \\ $$$$\underset{\left({i}\right)} {\underbrace{\mathrm{10}{x}+\mathrm{6}{y}=\mathrm{8}}}\:\:\wedge\:\:\:\underset{\left({ii}\right)} {\underbrace{\:\mathrm{2}{y}+\mathrm{4}{z}=\mathrm{5}}} \\ $$$$\left({i}\right)+\left({ii}\right): \\ $$$$\mathrm{10}{x}+\mathrm{8}{y}+\mathrm{4}{z}=\mathrm{13} \\ $$