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Need help with #9, & #10 please

Need help with #9, & #10 please-example-1
User Elie Teyssedou
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1 Answer

24 votes
24 votes

Explanation:

the line equation is in the slope-intercept form.

that looks like

y = ax + b

"a" is the slope (always the factor of x). "b" is the y-intercept (the y value when x = 0).

so, when it says "the same slope", we know we have to use the same factor of x.

and yes, the coordinates of a point are (x, y). so, you really need to use it in the places of x and y to get "b".

9.

y = -4x + b

2 = -4×0 + b = b

so, yes, the equation is

y = -4x + 2

but as you can see : b is NOT y in general.

10.

y = 2/3 x + b

-1 = 2/3 × 4 + b = 8/3 + b

now, let's multiply both sides by 3 to get rid of the fraction :

-3 = 8 + 3b

-11 = 3b

b = -11/3

so, the equation is

y = 2/3 x - 11/3

or

y = 1/3 × (2x - 11)

User Ryan Barrett
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2.7k points