Question 385320
x+4y=19
5x+y+0

Let's solve this one by elimination method. Multiply the second equation by 4, then subtract it from the first equation:


x+4y = 19
20x +4y = 0
-----------
-19x = 19


x= -1


Plug this value into either equation to find y:

5x+y = 0
5(-1) + y = 0
-5 + y = 0
y = 5


So the solution is (-1,5) or x=-1, y=5.


Second question is weird because it has no nice answers. Are you supposed to write your answers as fractions or as decimals? I did it with fractions:


a-b=25
3a+4b=4

Multiply the first equation by 3, then subtract.


3a - 3b = 75
3a + 4b = 4
--------------
0 - 7b = 71


b = -71/7


Plug this into either equation to find a:


3a - 3(-71/7) = 75
3a + 213/7 = 75
3a = 75- 213/7
3a = 312/7
a = 312/21
a = 104/7