Step-by-step explanation:
Given the simultaneous equation
5c+4p=18.40 ..... 2
2c+4p=11.20.......2
According to the equation given 7c+8p=29.60, we will see that the two equation was added to get the required equation in question. Note that this equation 7c+8p=29.60 cannot help us to solve the simultaneous equation because the resulting equation is one equation with two unknown variables. For us to get a solution to the simultaneous equation, we need to reduce the system of equation to just an equation and a variable. This can be gotten by taking the difference of the two equation as shown: (Elimination method)
Equation 1 - equation 2 will give;
(5c-2c)+(4p-4p) = 18.40-11.20
3c+0 = 29.60
3c = 29.60
Divide both sides by 3
3c/3 = 29.60/3
c = 9.87
Substitute c = 9.87 into equation 2
From 2: 2c+4p = 11.20
c + 2p = 5.60
9.87 + 2p = 5.60
2p = 5.60 - 9.87
2p= -4.27
p = -4.27/2
p = -2.135
You can see that what helped in solving the system of equation is by eliminating one of the variables first using the Elimination method.