4 math questions for 8th grade?

Question

 

Which shows solutions to x + 3y = 7 if x and y must be whole numbers.



A.
{(0, 5), (1, 3), (2, 1)}


B.
{(2, 1), (1, 4), (0, 7)}


C.
{(1, 2), (4, 1), (7, 0)}


D.
{(0, 5), (1, 4), (2, 1)}


What is the slope of a line parallel to the line with equation

5x – 2y = 11?



A.-11/2


B.-5/2


C.-2/5


D.5/2

Which ordered pair is on the graph of the equation 3x + 7y = 11?



A.(1, –2)


B.(0,–4)


C.(6, –1)


D.(0, 4)

What is the slope of a line perpendicular to the line with equation y = 4x + 5?
4
-4
-1/4
-5

Answer 1

Answers:

[1] Here we need to substitute the each pairs of x and y values and match the pairs.

caseA: x=0 and y=5   x+3y=7

0+3(5)=15 does not equal to 7

caseB: x=2, y=1

2+3(1)=5 does not equal to 7

case C: x=1 y=2

1+3(2)=7 equal to 7

now we need to consider second set of pair which is x=4, y=1

4+3(1)=7 equal to 7

last pair, x=7 and y=0

7+3(0)=7 equal to 7

All sets of pairs valid. Therfore answer should be C

 

[2] 5x-2y=11

2y= 5x-11

y=5/2 x-11/2

Therefore, slope should be 5/2, Answer D

 

[3] 3x+7y=11

Again, we need to substitute the values and check whether there are working or not

case A: (1,-2)   3(1)+7(-2)=3-14= -11 does not equal to 11

case B: (0,-4)  3(0)+7(-4)=0-28= -28

case C: (6,-1)  3(6)+7(-1)= 18-7= 11

therefore answer should be C

 

[4] the slope of the y= 4x+5 line is 4. However,the slope of the perpendicualr line should be negative of reciprocal value. Which is equal to -1/4

 

answer c