Question 190108
Substitution method---


From the first equation take out one variable in terms of the other and substitute it in the other equation.

we have:

{{{ x + y = 7/2 }}}
=> {{{ x = 7/2 - y }}}

Now, substitute this value of x, into equation 2.

{{{ 4x - 3y = -14 }}}
=> {{{ 4*(7/2 - y) - 3y = -14 }}}  (Now, use distributive law to open the brackets)
=> {{{ 14 - 4y - 3y = -14 }}}
=> {{{ 14 - 7y = -14 }}} (Next, bring -14 to the Left hand side by adding both sides by 14 and bring -7y to the Right hand side by adding both sides by 7y)
=> {{{ 14 + 14 = 7y }}}  (Next, Re-arrange the equation)
=> {{{ 7y = 14 + 14 }}}
=> {{{ 7y = 28 }}}
=> {{{ y = 28/7 }}}
=> {{{ highlight(y = 4) }}}

plug back this value of y into the value of x to obtain x.

=> {{{ x = 7/2 - y }}}
=> {{{ x = 7/2 - 4 }}}
=> {{{ highlight(x = -1/2) }}}

hope this helps.