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feodorn
Registered User Posts: **16** New Member

Improve Your SAT Scores with the SAT Skills Insight (why is it negative...?)

Improve Your SAT Scores with the SAT Skills Insight

I need a thorough explanation for the second one, please.

Improve Your SAT Scores with the SAT Skills Insight

I need a thorough explanation for the second one, please.

Post edited by feodorn on

This discussion has been closed.

## Replies to: I need help with the following Math questions!!

35Junior Memberit is negative because the slope is (y2-y1)/(x2-x1)

let r=4=y1 and s=5=x2

than, (0-4)/(5-0) is -4/5, which equals -r/s

you can tell if the slope is negative if it falls down to the right side, if it rises to the right side it is alway positive

btw i don't know the second one :D

99Junior MemberThere are two strategies for 2.

The first, more obvious is to factor each equation to find which one doesn't have x-1 as a factor

The second is much faster, but a little harder to notice.

If (x-k) is a factor of f(x), then f(k)=0. So, simply substitute 1 for x (make sure you realize it's the opposite of the number given, if it had said x+1, you would substitute -1)

All of them will equal 0 except e.

BTW this is a late ALG 1, early ALG 2 concept, if you need a more thorough explanation, I can explain it more in detail.

16New Member"btw i don't know the second one"

Let's hope someone else does. :p

16New MemberYou've lost me there with the function. More details would be good.

16New MemberAlso, which angle rules are needed to solve this?

99Junior Member99Junior MemberThe large triangle is isoceles, so you know that both base angles are equal.

180-40(the given angle)=140

since both angles are equal, divide by 2

140/2=70

Now you know both base angles are 70. Now work with the angle bisectors. The base angles of the smaller triangle must both = 35 because 70/2=35.

Now subtract those two angles from 180 to get 110.

180-35-35=110 answer a

16New Member99Junior MemberIn high school algebra, you will probably work mainly with parabolas, which are shaped like u's

When you have a quadratic function, it means y=ax^2+bx+c

where a, b, and c are coefficients, which will be given.

(In answer choice A, a=1, b=-3, and c=2)

When dealing with parabolas the main characteristics looked at are the vertex (bottom of the u if a is positive, top of the upsidedown u if a is negative)

Note: I'm just splitting it so I can know how much you need to know

99Junior MemberDue to the shape of a parabola, their graphs have the potential to pass through the x-axis 0 times or 2 times.

When it passes through 0 times you deal with complex numbers (numbers involving i - I don't think they appear on the SAT)

When it passes through twice, you can calculate its intercepts

99Junior Memberex. (2x+1)(x+1)=2x^2 + 3x + 1

16New MemberAnd I got up to the 70 degree angle step, but wasn't sure how to proceed. Thanks again.

99Junior MemberWhen factoring a quadratic equation, check if a is positive. If it is negative, multiply both sides of the equation by negative 1.

ex. -3x^2 +2x +2 ----> 3x^2-2x-2

next, list the factors a across from the factors of c, ignoring negatives

ex. x^2 + 2x + 1

-factors of a= 1,1

-factors of c=1,1

Now at this point, it gets tricky, and many different circumstances can happen, I will show you a simplified version.

set up two sets of parenthesis so that you have (?x+?)(?x+?).

Factors of a will be the question marks next to x, and factors of c will be question marks after the +. Our example limits the choices, making it much easier

so in our example x^2 + 2x + 1 = (x+1)(x+1)

99Junior MemberIf y=0 then it is an x intercept AND one of the two terms in the equation written as a product(factored) must equal 0 - (0 times anything will equal 0)

So each part of the factored equation can be set equal to 0 and then solved for x

(x+1)(X+1)=0

x+1=0

x=-1

The SAT problem is just giving you the reverse. If you know that x-1 is a factor, then you know that y=0 when x=1 (the sign changes when you solve for x). When you substitute 1 into the problem, if it doesn't equal 0, then you know that x-1 isn't a factor, and therefore, the choice you are looking for

16New MemberNow how do you figure out something like this in a timely manner

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