-7x -7y = 21
Y = 6
Since they are giving you the value of 6 you just plug it in the equation
-7x - 7(6) = 21
-7x - 42 = 21
+ 42. +42
-7x = 63
/-7. /-7
X = -9
The lowest number is 2/1 or 2.
reduce 8/4 to 4/2 which can be reduced to 2/1
The problem is already in standard form but to get it into slope intercept form you rewrite the equation so it looks like
6y=-5x+7 divide all by 6
y=-5/6x+7/6
slope being -5/6 and b being 7/6
It would take 630 seconds to boil the water.