solve the following system of equations using the substitution method

Question

x=y+7

2x+y=5

 

the solution is. _ (type an ordered pair)

Answer 1

Hello George, Glad to help you with this one: Step one: First write the two equations separately side by side:          X=Y +7                         2X+Y=5

Now use the equation 2X+Y=5 (write this down).  Do you see where the letter X is in this equation?  Now.

put the x=y+7 where the X is. It will look like this:     2(Y+7) +Y=5 Now MULTIPLY the TWO by what is inside the parenthesis, Now it will look like this:   2Y+14+Y=5.  Now it becomes a simple equation, Now solve.

       First ADD the Y's   giving you  3Y+14=5. Now Subtract 14     from both sides. Now, the equation looks

like this:3y=-9, Next, divide both sides by 3 and Y=-3  Now, replace the -3 in the Y position in the

2X+Y=5 equation, looking like this: 2X+(-3)=5. Now ADD a plus 3 to both sides. Now the equation looks like

                2x=8. Divide both sides by two giving X=4. Now substitute the X=4 and Y= -3 into the X=Y +7 equation. Now you have: 4=(-3) +7 giving 4=4, Next, other equation 2(4) +(-3) =5  8+(-3)=5, 5=5

Coordinates are X=4 and Y=(-3)      (4,-3)------->Answer