[tex]\bold{\huge{\red{\underline{ Solution}}}}[/tex]
[tex]\bold{\underline{ We \: have\: given :-}}[/tex]
[tex]\sf{ 7x - 3y = 20. ...eq(1 ) }[/tex]
[tex]\sf{ y = 5x - 4. ...eq(2) }[/tex]
Here, we will use the substitution method for solving the above equations.
[tex]\bold{\underline{Subsitute \: eq(1)\:in \: eq(2)}}[/tex]
[tex]\sf{ 7x - 3(5x - 4) = 20 }[/tex]
[tex]\sf{ 7x - 15x + 12 = 20}[/tex]
[tex]\sf{ - 8x + 12 = 20 }[/tex]
[tex]\sf{ - 8x = 20 - 12 }[/tex]
[tex]\sf{ - 8x = 8}[/tex]
[tex]\sf{ x = 8/-8}[/tex]
[tex]\sf{ x = - 1. ...eq( 3 )}[/tex]
[tex]\bold{\underline{Subsitute \: eq(3)\:in \: eq(2)}}[/tex]
[tex]\sf{ y = 5(-1) - 4 }[/tex]
[tex]\sf{ y = - 5 - 4 }[/tex]
[tex]\sf{ y = - 9 }[/tex]
[tex]\sf{\blue{ Hence, \: The \:value \:of \:x \:and \:y \:is\: - 1 \: and \:-9}}[/tex]
