Question 90073
Solve by substitution:
1) {{{5x-2y = -5}}}
2) {{{y-5x = 3}}} Solve this equation for y and substitute into the first equation then solve for x.
2a) {{{y = 5x+3}}} Substitute into equation 1).
1a) {{{5x-2(5x+3) = -5}}} Solve for x.
{{{5x-10x-6 = -5}}} Combine like-terms.
{{{-5x-6 = -5}}} Add 6 to both sides.
{{{-5x = 1}}} Divide both sides by -5.
{{{x = -1/5}}} Now substitute this value of x into equation 2a) and solve for y.
2a) {{{y = 5(-1/5)+3}}} Simplify.
{{{y = -1+3}}}
{{{y = 2}}}
The solution is: (-1/5, 2)
Check by graphing:
{{{graph(600,400,-5,5,-5,5,(5/2)x+5/2,5x+3)}}}
The solution is indicated by the intersection of the two lines.