How do I use substitution to solve a system of linear equations?

for example:

y=2x+4

 3x+y=9

We can substitute y in the second equation with the first equation since y = 2x+4.

  3x+(2x+4)=9

5x+4=9

5x=5

x=1

answer is 144

step-by-step explanation:

answer: on graphs, the open and closed circles, or vertical asymptotes drawn as dashed lines us identify discontinuities.

as before, graphs and tables allow us to estimate at best.

when working with formulas, getting zero in the denominator indicates a point of discontinuity.

when working with piecewise-defined functions, check for discontinuities at the transition points where one piece ends and the next begins.

step-by-step explanation: