Question

I need help finding the point and slowing the system of equations using substitution :( !!

Answer 1

The method of Substitution is very simple to understand. This method literally means that you replace something with something of the same value. For example when I say,

Keisy = Girl, it means that Keisy is a girl, therefore it also means that a girl can also be Keisy.

And in terms of math for example we have,

a = b , it means that a is the same as b, so when we see and expression for example:

b + c = 10, it is the same as saying,

a + c = 10, because a is just the same as b, and b is also just a.

We can see that the b is replace or substituted with a, therefore this method is calle substitution.

So for our problem we have the expressions.

y = 2x, and

x + y = 12

Note that in the first expression it says that y = 2x (y is equal to 2x, or y is just the same as 2x). Therefore since y is just the same as 2x, we can replace (substitute) the "y" in the second expression with 2x. Giving us the equation:

$\begin{gathered} x+y=12\text{ , where y=2x} \\ x+(2x)=12_{}_{} \\ x+2x=12 \\ 3x=12 \\ x=\frac{12}{3} \\ x=4 \end{gathered}$

Therefore x = 4, it means that x is just equal to 4, and since our y is just 2x (2 times the x) based on our first expression. We get the following value:

$\begin{gathered} y=2x\text{ , where x=4} \\ y=2(4) \\ y=8 \end{gathered}$

Therefore our y = 8.

So the answer for our question is LETTER A. (4, 8)