Question

Solve, using the method of substitution

1.5x + 0.1y = 6.2, 3x – 0.4y = 11.2

Answer 1

1.5x + 0.1y = 6.2

Multiply by 10

15x + y = 62

y = 62 – 15x → (1)

3x – 0.4y = 11.2

Multiply by 10

30x – 4y = 112

Divided by (2) we get

15x – 2y = 56 → (2)

Substitute the value of y in (2)

15x – 2(62 – 15x) = 56

15x – 124 + 30x = 56

45x = 56 + 124

45x = 180

x = `180/45`

= 4

Substitute the value of x = 4 in (1)

y = 62 – 15(4)

= 62 – 60

y = 2

∴ The value of x = 4 and y = 2