Question Number 122760 by mulindwahakiim last updated on 19/Nov/20
$$\mathrm{3}{x}+{y}=\mathrm{6} \\ $$$${x}−\mathrm{5}{y}=\mathrm{12} \\ $$
Commented by MJS_new last updated on 19/Nov/20
$$\mathrm{seriously}?\:\mathrm{what}\:\mathrm{is}\:\mathrm{it}\:\mathrm{you}\:\mathrm{don}'\mathrm{t}\:\mathrm{understand}? \\ $$
Answered by bemath last updated on 19/Nov/20
$$\begin{pmatrix}{\mathrm{3}\:\:\:\:\mathrm{1}}\\{\mathrm{1}\:\:−\mathrm{5}}\end{pmatrix}\:\begin{pmatrix}{{x}}\\{{y}}\end{pmatrix}\:=\:\begin{pmatrix}{\mathrm{6}}\\{\mathrm{12}}\end{pmatrix} \\ $$$$\Delta\:=\:−\mathrm{16}\:,\:\Delta_{{x}} \:=\:\begin{vmatrix}{\mathrm{6}\:\:\:\:\:\:\:\:\:\mathrm{1}}\\{\mathrm{12}\:\:\:\:\:−\mathrm{5}}\end{vmatrix}=\:−\mathrm{42} \\ $$$$\Delta_{{y}} \:=\:\begin{vmatrix}{\mathrm{3}\:\:\:\:\:\:\:\mathrm{6}}\\{\mathrm{1}\:\:\:\:\:−\mathrm{5}}\end{vmatrix}=\:−\mathrm{21} \\ $$$$\rightarrow\begin{cases}{{x}\:=\:\frac{\Delta_{{x}} }{\Delta}\:=\:\frac{\mathrm{42}}{\mathrm{16}}\:=\:\frac{\mathrm{21}}{\mathrm{8}}}\\{{y}\:=\:\frac{\Delta_{{y}} }{\Delta}\:=\:\frac{\mathrm{21}}{\mathrm{16}}}\end{cases} \\ $$
Commented by MJS_new last updated on 19/Nov/20
$$\mathrm{yes}\:\mathrm{but}\:\mathrm{do}\:\mathrm{you}\:\mathrm{believe}\:\mathrm{this}\:\mathrm{will}\:\mathrm{help}\:\mathrm{this}\:\mathrm{person}? \\ $$
Commented by bemath last updated on 19/Nov/20
$${hahaha}....{i}\:{don}'{t}\:{know}\:{sir}.. \\ $$
Commented by bemath last updated on 19/Nov/20
$${my}\:{be}\:{he}\:{is}\:{just}\:{kidding}\: \\ $$
Commented by 676597498 last updated on 19/Nov/20
$${stop}\:{intimidating}\:{people} \\ $$$${do}\:{u}\:{know}\:{if}\:{he}/{she}\:{is}\:{still}\:{in} \\ $$$${secondary}\:{school}\:{lower}\:{class}? \\ $$$${stop}\:{spoiling}\:{ur}\:{reputation} \\ $$$${if}\:{u}\:{dont}\:{want}\:{to}\:{help}\:{someone}, \\ $$$${dont}\:{be}\:{talking}\:{so}\:{stupidly}...{sorry}\:{to}\:{say} \\ $$
Commented by bemath last updated on 19/Nov/20
why are you angry? nothing intimidating here. so take it easy. no need to be angry like that.
Commented by MJS_new last updated on 19/Nov/20
$$\mathrm{that}'\mathrm{s}\:\mathrm{why}\:\mathrm{I}\:\mathrm{asked}\:``\mathrm{what}\:\mathrm{is}\:\mathrm{it}\:\mathrm{you}\:\mathrm{don}'\mathrm{t} \\ $$$$\mathrm{understand}''.\:\mathrm{expecting}\:\mathrm{an}\:\mathrm{answer}\:\mathrm{so}\:\mathrm{I}\:\mathrm{can} \\ $$$$\mathrm{help}\:\mathrm{as}\:\mathrm{needed}. \\ $$
Commented by Ar Brandon last updated on 19/Nov/20
This is his first post and it's possible that he maybe testing the app or the forum.