Solve the system by the addition method: 3x=4 - 5y 4x - 5y=3. What is x?

Answer 1

These are solved using simultaneous equations
3x =4-5y becomes
3x + 5y =4 because you add 5y to both sides
if you add this to the equation 4x - 5y = 3
the ys cancel out and you get
7x =7
so x=1
if you substitute this into the second equation you get
4-5y=3
so 4=3+5y
so 1=5y
y=1/5 or 0.2

Answer 2

always when you see two equations which both equal to a number and both contain y and x , dont hesitate to use simultanous equations method, when the sign ofadding and subtracting are same you have to subtract th whole equation but when different you hav to add them up:

3x =4-5y becomes
3x + 5y =4 because you add 5y to both sides
if you add this to the equation 4x - 5y = 3
the ys cancel out and you get
7x =7
so x=1
then substitude this in the second one
4-5y=3
so 4=3+5y
so 1=5y
y=1/5 or 0.2

Answer 3

3x = 4 - 5y
4x = 3 + 5y (take y to the RHS)

Adding them we get 7x = 7 and x = 1

When we substitute the value of x in first equation, we get

3 = 4 - 5y or - 1 = - 5y or y = 1/5

When we substitute the x and y value in second equation, we get

4 - 1 = 3 and hence we can write x = 1 and y = 1/5 as the solution.

Answer 4

4x-5y=3 => x=(3+5y)/4
3x=4-5y => (9+15y)/4=4-5y=>9+15y=16-20y=>35y=25=>y=5/7