precalculus II work & answer check

Question 1.

Correct option=d

When you expand the equation:

4x-8+6x=12

10x=12+8

10x=20

x=20/10

Ans: x=2

Question 2.

Correct option=d

20+10x-70=5x+20+5x

Putting the like terms together;

0=70

Ans: no solution

Question 3.

Correct option=b

The l.c.m(least common denominator) of the equation is +y-12.thus the equation is:

Thus the equation changes to:

5y-15+11-7y-28=0 ; since the denominator when multiplied with a zero is equal to a zero

Putting like terms together:

-2y=+32

Y=-16

Ans: y=-16

Question 4.

Correct option=b

x=12*20/100 x=2.4 gallons

calculating for the additional one, 0.4=(y+2.4)/(12+y) 4(12+y)=10(y+2.4) 48+4y=10y+24 6y=24 y=4 gallons

Question 5:

Correct option=b

Absolute means the value is positive.Thus:

Ans:11-

Question 6

Correct option=a

This statement means even if you subtract 5 from x,the absolute value is greater than 6.

Ans:

Question 7.

Correct option=b

This means the absolute value from the equation is 8. Thus:

-x=

-x=-11 or 5

Ans:x=11,-5

Question 8

Correct option=c

This means:

x=-2 or

Ans:(-2,)

Question 9.

Correct option=a

2x-11=

2x=20 or 2

x=10,1

Ans:10,1

Question 10.

Correct option=a

Like terms together:

Ans:-14+3i

Question 11.

Correct option=c

If you expand the equation, it will add up to:

-7i+14i^2. but in multiplication if there is ‘i^2’ part, the number with which it is multiplied changes to a total negative sign and we omit it. In simple words the value if i^2 is -1thus the answer is:

-14-7i.

Question 12.

Correct option=d

After expanding the equation,

9+15i-15i-25i but as said before, the multiplication of two ‘i’ parts changes to a total negative value.thus the answer is:9-(-25)

It changes to be:9+25

Ans:34

Question 13.

Correct option=b

Multiply the numerator and the denominator with 4-3i. this will eliminate the standard form of the denominator.

Ans:

Question 14.

Correct option=c

Using the completing the square technique, you calculate by adding the square of half the coefficient of x.

Question 15.

Correct option=a

3+18x=0

factorizing

(3x)(x+6)=0

3x=0 and x+6=0

Ans: x=-6 or 0

Question 16.

Correct option=c

x+4=

Ans:x=-4

Question 17.

Correct option=d

Ans: x=-2

Question 18.

Correct option=c

Ans: x=3

Question 19.

Correct option=c

9

x(9x+5)=0

Ans:x=

Question 20.

Correct option=a

5x+1=9

9

x(9x+1)=0

Ans:x=0