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Solve the given system of equations using the Substitution Method.
Solutions: (3,0) and (4,1)
Graph:
Notice that the y-variable is already isolated in Equation (II). Therefore, the most convenient method to solve the given system of equations is the Substitution Method. y^2=x-3 & (I) y=x-3 & (II) Let's substitute x-3 for y in Equation (I).
(I): y= x-3
(I):(a-b)^2=a^2-2ab+b^2
Calculate power and product
(I): LHS-x=RHS-x
(I): LHS+3=RHS+3
Notice that in Equation (I) we have a quadratic equation in terms of only the x-variable. There are many ways to solve this type of equation. We will use the Quadratic Formula. Let's determine a, b, and c. x^2-7x+12=0 ⇔ 1x^2+( - 7)x+ 12=0
Substitute values
We can calculate the first root using the positive sign and the second root using the negative sign.
| x=7± 1/2 | |
|---|---|
| x=7+ 1/2 | x=7- 1/2 |
| x=4 | x=3 |
Now consider Equation (II). y=x-3 We can substitute x=4 and x=3 into the above equation to find the values for y. Let's start with x=4.
We found that y=1 when x=4. One solution of the system is (4,1). To find the other solution, we will substitute 3 for x in Equation (II) again.
We found that y=0, when x=3. Therefore, our second solution is (3,0).
Notice that Equation (I) represents a parabola and Equation (II) represents a line. If you need explanations on graphing parabolas, please see this example. If you need explanations on graphing lines, please see this other example. Let's graph them and mark the points (4,1) and (3,0)!
The parabola and the line intersect at the points (4,1) and (3,0), which confirms our answer.