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SIZIF [17.4K]
2 years ago
7

Which expression is equivalent to x² - 4x - 45?

Mathematics
2 answers:
dolphi86 [110]2 years ago
7 0

Answer:

D

(x - 9)(x+5)

Step-by-step explanation:

x² + 5x - 9x - 45

x · (x + 5) - 9 (x + 5)

(x - 9) (x + 5)

lisabon 2012 [21]2 years ago
6 0

Answer:

D. (x - 9)(x+5)

Step-by-step explanation:

x^{2} - 4x - 45 is your expression, so you have to factor it out. Since from the options available it's clear that the factors of -45 you use are some form of 9 and 5, we can use the process of elimination to figure out which are the correct ones.

First, through FOIL u know that in any factored form the last two terms in each bracket multiply together to make the last term in the expanded form.

So first, look at A. the last two terms are -9 and -5, which = 45 when multiplied together. 45 does not = -45, so it can't be A.

B has 9 and 5. When they're multiplied, they = 45, which does not = -45, so its not B

It can't be C either, because the first term of the first bracket in C is 20, and when multiplied with x it doesn't produce x^2.

Therefore it has to be D. u can check this by multiplying -9 and 5, which = -45, the final term in the expanded form. Also, -9 + 5 = -4, which is the middle term of the expanded form.

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Can someone pls help??
Vlad1618 [11]

Answer:

a. The y coordinates for A are either 10 or -14

b.  The y coordinates for A are either -11 or 7

Step-by-step explanation:

distance = sqrt ((x2-x1)^2+(y2-y1)^2)

We know Point B and the x coordinate of point A as well as the distance

15 = sqrt ((-4-5)^2+(-2-y1)^2)

15 = sqrt ((-9)^2+(-2-y1)^2)

15 = sqrt (81+(-2-y1)^2)

Square each side

15^2 =sqrt (81+(-2-y1)^2)^2

225 =  81+(-2-y1)^2

Subtract 81 from each side

225-81 = 81-81 +(-2-y1)^2

144 = (-2-y1)^2

Take the square root of each side

±sqrt 144 = sqrt(-2-y1)^2

±12 = (-2-y1)

Add 2 to each side

2±12 = 2-2-y1

2±12 = -y1

14 = -y1  or -10 = -y1

Multiply by -1

-14 = y1  or 10 = y1

The y coordinates for A are either 10 or -14

Now move B to -7,-2

15 = sqrt ((-7-5)^2+(-2-y1)^2)

15 = sqrt ((-12)^2+(-2-y1)^2)

15 = sqrt (144+(-2-y1)^2)

Square each side

15^2 =sqrt (144+(-2-y1)^2)^2

225 =  144+(-2-y1)^2

Subtract 144 from each side

225-144 = 144-144 +(-2-y1)^2

81 = (-2-y1)^2

Take the square root of each side

±sqrt 81 = sqrt(-2-y1)^2

±9 = (-2-y1)

Add 2 to each side

2±9 = 2-2-y1

2±9 = -y1

11 = -y1  or -7 = -y1

Multiply by -1

-11 = y1  or 7 = y1

The y coordinates for A are either -11 or 7

3 0
3 years ago
CAN SOMEONE PLEASE PLEASE PLEASE HELP ME, YOU’LL GET FREE EASY POINTS IF YOU GIVE ME THE RIGHT ANSWER !!
bekas [8.4K]

Answer:

  1. reflection across BC
  2. the image of a vertex will coincide with its corresponding vertex
  3. SSS: AB≅GB, AC≅GC, BC≅BC.

Step-by-step explanation:

We want to identify a rigid transformation that maps congruent triangles to one-another, to explain the coincidence of corresponding parts, and to identify the theorems that show congruence.

__

<h3>1.</h3>

Triangles GBC and ABC share side BC. Whatever rigid transformation we use will leave segment BC invariant. Translation and rotation do not do that. The only possible transformation that will leave BC invariant is <em>reflection across line BC</em>.

__

<h3>2.</h3>

In part 3, we show ∆GBC ≅ ∆ABC. That means vertices A and G are corresponding vertices. When we map the congruent figures onto each other, <em>corresponding parts are coincident</em>. That is, vertex G' (the image of vertex G) will coincide with vertex A.

__

<h3>3.</h3>

The markings on the figure show the corresponding parts to be ...

  • side AB and side GB
  • side AC and side GC
  • angle ABC and angle GBC
  • angle BAC and angle BGC

And the reflexive property of congruence tells us BC corresponds to itself:

  • side BC and side BC

There are four available congruence theorems applicable to triangles that are not right triangles

  • SSS -- three pairs of corresponding sides
  • SAS -- two corresponding sides and the angle between
  • ASA -- two corresponding angles and the side between
  • AAS -- two corresponding angles and the side not between

We don't know which of these are in your notes, but we do know that all of them can be used. AAS can be used with two different sides. SAS can be used with two different angles.

SSS

  Corresponding sides are listed above. Here, we list them again:

  AB and GB; AC and GC; BC and BC

SAS

  One use is with AB, BC, and angle ABC corresponding to GB, BC, and angle GBC.

  Another use is with BA, AC, and angle BAC corresponding to BG, GC, and angle BGC.

ASA

  Angles CAB and CBA, side AB corresponding to angles CGB and CBG, side GB.

AAS

  One use is with angles CBA and CAB, side CB corresponding to angles CBG and CGB, side CB.

  Another use is with angles CBA and CAB, side CA corresponding to angles CBG and CGB, side CG.

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aleksandr82 [10.1K]

Answer:

b = -8

Step-by-step explanation:

6b = -42

Divide by 6 on both sides

b = -8

8 0
3 years ago
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Tcecarenko [31]
62 because 90 minus 15, minus 13, is equal to 62
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3 years ago
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-3b+7=13 solve for b
sleet_krkn [62]

Answer:

b =-2

Step-by-step explanation:

-3b+7=13

Subtract 7 from each side

-3b+7-7=13-7

-3b = 6

Divide each side by -3

-3b/-3 = 6/-3

b = -2

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3 years ago
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