Question

Y = 2x + 3 y = -2x + 15 Can you please explain how to get the answer.

Answer 1

Answer:

$x = 3$ and $y = 9$

Step-by-step explanation:

Given:

$y = 2x + 3$ .......................... equation i

$y = -2x + 15$ ........................ equation ii

since y is equals to the two functions , we can equate the two values of y . That is , equate equation i and ii , we have

$2x + 3 = -2x + 15$

Add $2x$ to both sides , we have

$2x + 2x + 3 = -2x + 2x + 15$

$4x + 3 = 15$

subtract 3 from both sides , we have

$4x = 12$

divide both sides by 4 , then

$x = 3$

substitute $x = 3$ into equation i to get the value of y , that is

$y = 2(3) +3$

$y = 6 + 3$

$y = 9$

Therefore :

$x = 3$ and $y = 9$

Answer 2

Answer:

x =3 and y = 9

Step-by-step explanation:

This is a simultaneous equation

y = 2x + 3      is equation 1

y = -2x + 15    is equation 2

Using the elimination method, we will add the two equations together

Then, we will have

2y = 18

Note that y+y =2y, 2x+(-2x) = 0 and 3+15 =18

y = 18/2  (dividing both sides by 2)

Therefore, y = 9.

Since we know the value of y, we can substitute 9 for y in any of the equation.

Lets substitute 9 for y in equation 1, we will have

9 = 2x + 3

collecting like the like terms

9 - 3 = 2x

6 = 2x

if we divide both sides by the coefficient of x, which is 2, we will have

x = 6/2

x = 3

Therefore x = 3 and y = 9