Answer:
x = 7, y = 6
Step-by-step explanation:
solve for y for the first equation
2x + y = 20
-2x -2x , eliminate 2x
y = 20-2x
now that we have found y, substitute the y in for the second equation
-5y = -6x + 12
-5(20-2x) = -6x + 12, we just changed y into 20-2x. remember that we are multiplying all of 20 - 2x by -5
-100+10x = -6x + 12, we multiplied everything from the parathesis by -5
+100 + 100, eliminate -100
10x = -6x + 112
+6x +6x , eliminate 6x
16x = 112 , solve for x
x = 7
then y = 20 - 2x = 20 - 2*7 = 6
check:
2 * 7 + 6 = 20
20 = 20
-5 * 6 = -6 * 7 + 12
-30 = -42 + 12
-30 = -30
Answer:
a) - 11x - 94y / 12 b) x -4 / 5- 3x c) 12x - 11 /10y
Step-by-step explanation:
a) 2x - 6y / 4 - 4y - x/ 12 - 4x - 20y /3
6x - 18y / 12 - 4y - x / 12 - 16x - 80y / 12
= 5x - 14y / 12 - 16x - 80y / 12
- 11x - 94y / 12
b) x /5 - 4/ 3x = x -4 / 5- 3x
c) 2x -3/ 5y - 5- 2x / 10y + x/y
4x - 6 /10y - 5-2x/ 10y + 10x / 10y
2x - 11 / 10 + 10x / 10y
= 12x - 11 /10y
