Question 995752

{{{ y=7x}}}.......eq.1
{{{4x - y = -12}}}.......eq.2
----------------------------------substitute {{{7x}}} for {{{y}}} in eq.2

{{{4x - 7x = -12}}}.......eq.2....solve for {{{x}}}

{{{- 3x = -12}}}......both sides multiply by {{{-1}}}

{{{(-1)(- 3x) = (-1)(-12)}}}

{{{3x = 12}}}

{{{x = 12/3}}}

{{{highlight(x = 4)}}}

go back to eq.1,substitute {{{4}}} for {{{x}}}

{{{ y=7*4}}}.......eq.1

{{{ highlight(y=28)}}}

solution to this system:

{{{highlight(x = 4)}}} and {{{ highlight(y=28)}}}

it means given lines intersect at point ({{{4}}},{{{28}}})


{{{drawing( 600, 600, -10, 10, -10, 35,
circle(4,28,.16),locate(4,28,p(4,28)),
 graph( 600, 600, -10, 10, -10, 35, 7x,4x+12)) }}}