Question

Solve each pair of simultaneous equations by elimination method.
a) 2x+3y-1=0
5x+2y+3=0​

Answer 1

make x the subject
2x = -3y + 1
5x = -2y -3

now times the answers to get the lcd

(2x = -3y + 1) x 5
10x = -15y + 5

(5x = -2y -3) 2
10x = -4y -6

now that they are equal to the same number:
-15y + 5 = -4y -6
-15y + 4y = -6 -5
-11y = -11
y = 1

now to find x we substitute y
2x = -3y + 1
2x = -3(1) + 1
2x = -3 + 1
2x = -2
x = -1

Answer 2

Answer:

x = -1

y = 1

Step-by-step explanation:

PART I: Find the y-value

Given expressions

1) 2x + 3y - 1 = 0

2) 5x + 2y + 3 = 0

Add 1 on both sides of the 1) equation:

2x + 3y - 1 + 1 = 0 + 1

2x + 3y = 1

Subtract 3 on both sides of the 2) equation:

5x + 2y + 3 - 3 = 0 - 3

5x + 2y = -3

Current System

1) 2x + 3y = 1

2) 5x + 2y = -3

Multiply 2.5 on both sides of the 1) equation

(2.5) 2x + (2.5) 3y = (2.5) 1

5x + 7.5y = 2.5

Current System

1) 5x + 7.5y = 2.5

2) 5x + 2y = -3

Subtract 2) equation from 1) equation

(5x + 7.5y) - (5x + 2y) = 2.5 - (-3)

Get rid of the parenthesis

5x + 7.5y - 5x - 2y = 2.5 + 3

Combine like terms

5x - 5x + 7.5y - 2y = 5.5

0 + 5.5y = 5.5

5.5y = 5.5

Divide 5.5 on both sides

5.5y / 5.5 = 5.5 / 5.5

$\boxed{y=1}$

PART II: Find the x-value

Substitute the y-value back to one of the equations to find the x-value

2x + 3y - 1 = 0

2x + 3(1) - 1 = 0

Combine like terms

2x + 3 - 1 = 0

2x + 2 = 0

Subtract 2 on both sides

2x + 2 - 2 = 0 - 2

2x = -2

Divide 2 on both sides

2x / 2 = -2 / 2

$\boxed{x=-1}$

Hope this helps!! :)

Please let me know if you have any questions