Solve the following system of simultaneous equations 7a 5b

Solve the following system of simultaneous equations. 7a + 5b = 19.5 and 5a + 10b = 30

Solution

7a + 5b = 19.5......................(1)

5a+10b = 30

=> a + 2b = 6......................(2)

eq(2) * 7 - eq(1)

7a+14b-7a-5b = 42-19.5

9b = 22.5

b = 5/2

so,

a = 6-2b

a = 6 - 5

a = 1