Pleas help with the khan academy question
1 answer:
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Answer:
See description below.
Step-by-step explanation:
To choose the correct equation, find the slope of the line on the graph. Identify two points on the line. Then subtract to find their rate of change using the slope formula.
When you know the slope, find the negative reciprocal. For example, if the slope is 2/1 then the negative reciprocal is -1/2. This is the slope of a perpendicular line to a line with slope 2. Choose the equation which has this same slope.
Example:
y = 2x -1
y= -1/2 +5
Remark
There is no short way to do this problem and no obvious way to get the answer other that to solve each part.
Solve
A
Multiply by 2
x + 1.6 = 2(x + 0.1) Remove the brackets
x + 1.6 = 2x + 0.1*2
x + 1.6 = 2x + 0.2 Subtract x from both sides
1.6 = x + 0.2 Subtract 0.2 from both sides
1.6 - 0.2 = x
1.4 = x
Circle A
B
Subtract 2x from both sides.
3x - 2x = 1.4
Circle B
C
Remove the brackets.
4x + 6 = 2x - 6 Add 6 to both sides
4x + 12 = 2x Subtract 4x from both sides.
12 = -2x Divide by - 2
12/-2 = x
x = - 6 Don't circle C
D
I'm going to be very scant in my solution of this. You can fill in the steps.
3x = 4.2
x = 4.2/3
x = 1.4
Circle D