ANSWER: 18
EXPLANATION:
y=kxzw
where k is a constant
Making k the subject of the formula, we have
k=y/xzw
Inputting the values
k= 72/(2)(1)(12)
k=72/24
k = 3
Solving for y when x=1,z=2 and w=3
We have
y=kxzw
y = (3)(1)(2)(3)
y = 18
You can reword the two equations as:
-5x-y=15 (Divide original value by 3)
-2x+6y=6
Then use elimination to find x:
-30x-6y=90 (Multiply by 6 to get y values to be same to cancel out)
-2x+6y=6
You're left with:
-32x=96. Which can then be solved to find x which is -3.
Then plug back in
-2x+6y=6
Now to: -2(-3)+6y=6.
Which reduces to 6+6y=6. So y=0.
To graph them, just reword the equations (yes once again) so that y is in front.
y=-5x-15 and y=(1/3)x+1
Direct variation means that changes in x will result to changes in y. If x increase, y also increases and vice versa.
y = kx
k = y / x
y = 45 ; x = 40
k = 45/40
k = 1.125
y = 1.125x
y will increase by 1.125 interval of x.
