Question

Solve the system of equations using the substitution method.
-5x + 21 = 18
y= 2x+8

Answer 1

(-3;2)

Explanation:

if the first equation is -5x+21=18y, then:

`\left \{ {{y=2x+8} \atop {-5x+21=18*(2x+8)}} \right. \ => \ \left \{ {{y=2x+8} \atop {-5x+21=36x+144}} \right. \ => \ \left \{ {{y=2x+8} \atop {41x=-123}} \right. \ => \ \left \{ {{y=2} \atop {x=-3}} \right.`