Buying it 10% discount without tax is the best option. With card you still have the tax plus the card fee you pay annually to add to it. On the online purchase, you still have the tax plus the 5 shipping charge.
(6x+9y=78) - (6x+4y=38) = (5y=40) = y=8
(2x+3(8)=26) = (2x+24=26) = (2x=2) = x=2
Answer:
y = -1/3x + 2
Step-by-step explanation:
The gradient of the given line is 3 because (y = mx +c where m is the gradient)
Therefore, to find the gradient of the perpendicular line (at 90 degrees), you need to find the negative reciprocal.
The negative reciprocal of 3 is -1/3 because imagine if 3 = 3/1, to get the reciprocal, you flip it, and to get the negative, you just flip the sign.
Now we know that Line M is y = -1/3x + c, we need to find the y-intercept.
To do this, just input the point (3,1) into y = -1/3x + c, to get c. This is because we know (3,1) is on the line from the question.
So it would be 1 = (-1/3 x 3) +c
Which would be 1 = -1 +c
And so c = 2
Put everything together and you get y = -1/3x + 2
1-(1/5)= 4/5 or 28/35 if you multiply top and bottom by 5
