Question

Solve the follwoing for x and y using substitution method:
2.5x + 10y = 10, 3x - 12y = 24

• A. x = 6, y = -0.5
• B. x = 2, y = -0.5
• C. x = -6, y = 2
• D. x = -6, y = 0.5

Answer 1

The correct option is A x = 6, y = -0.5

2.5x + 10y = 10 --------(i)

3x - 12y = 24 --------(ii)

From equation (ii),

$\text{x}=\frac{12y+24}{3}$

x = 4y + 8 --------(iii)

Plug this value in equation (i)

2.5(4y + 8) + 10y = 10

$⟹$10y + 20 + 10y = 10

$⟹$20y = -10

$⟹$ y = $-\frac{10}{20}$

$⟹$ y = $-\frac{1}{2}$

$⟹$ y = -0.5

Plug the value of y in equation (iii):
x = 4y + 8

$⟹$ x = $-\frac{4}{2}$ + 8

$⟹$ x = -2 + 8

$⟹$ x = 6

The values of x and y are 6 and -0.5.