Question

Pls help
Solve by substitution.
6x +Зу = 15
x – 2y = 10

Answer 1

y=5 , x= 20

Explanation:

6x + 3y = 15

x - 2y = 10

make x subject of the formula in equation two

therefore x = 10 - 2y

substitute the value of x in equation one

6 ( 10 - 2y) + 3y = 15

60 - 12y + 3y = 15

-9y = -45

y = 5 and x = 20

Answer 2

{x,y} = {4,-9}

Explanation:

// Solve equation [1] for the variable y

[1] y = -6x + 15

// Plug this in for variable y in equation [2]

[2] -7x - 2•(-6x+15) = -10

[2] 5x = 20

// Solve equation [2] for the variable x

[2] 5x = 20

[2] x = 4

// By now we know this much :

x = 4

y = -6x+15

// Use the x value to solve for y

y = -6(4)+15 = -9

Solution :

{x,y} = {4,-9}