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Solve the following system of equations by using the substitution method. x = y + 3 2x...
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What we need to do is to use one of the equations to give us enoguh information to solve the other. For example, we have,
x = y+3
Knowing this, we can replace all the x in the second equation with y+3,
2(y+3) + y = 9
Notice that we now only have to solve for one variable - y - instead of x and y. This gives,
3y + 6 = 9
3y = 3
y = 1
Now that we have a value for y, we can substitute it into your equations to solve for x,
x = y + 3
x = (1) + 3
x = 4
Notice that y = 4 and x = 1 solves both of your equations at the same time.
Posted by jmelchior on July 27, 2013 at 12:35 AM (Answer #1)
High School Teacher
Using substitution to solve for x and y:
The first equation is already in a suitable format: x= y+3
Therefore we can substitute straight into the second:
2x+y=9 becomes 2(y+3) +y=9
Now solve for y
Now use your original equation to find x
`therefore x=y+3` becomes `x=1+3`
Ans:(4;1) x=4 y=1
Posted by durbanville on July 27, 2013 at 5:44 AM (Answer #2)
let x=y+3 be equation 1 and 2x+y=9 be equation 2
by the substitution method, x is already the subject in eqn. 1 so we simply substitute it into eqn. 2 this gives us......
knowing the value of y,
Posted by user4825270 on July 27, 2013 at 8:45 PM (Answer #3)
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