Question

which method would be most efficient to solve the system?
y=1/2x
2x+3y=28

a. graphing
b. substitution
c. elimination
d. distributive

Answer 1

i think its b

Answer 2

correct.

Answer 3

thats what I would do....sub

Answer 4

and what would the solution be

a.(2,3)
b. (8,4)
c. (7,3.5)
d. (2,14)

Answer 5

y = 1/2x
sub that in for y in the other equation

2x + 3y = 28
2x + 3(1/2x) = 28
2x + 3/2x = 28
4/2x + 3/2x = 28
7/2x = 28
x = 28/(7/2)
x = 28 * 2/7
x = 56/7
x = 8

y = 1/2x
y = 1/2(8)
y = 8/2
y = 4

answer is (8,4)

Answer 6

for the following system of equations, what is the x-vaule of the solution?
-x+2y=6
6y=x+18

a. -1
b. 0
c. 1
d. 6

Answer 7

-x + 2y = 6
-x = -2y + 6 -- multiply by -1 to make x positive
x = 2y - 6
now sub this in for x in the other equation

6y = x + 18
6y = 2y - 6 + 18
6y - 2y = -6 + 18
4y = 12
y = 3

-x + 2y = 6
-x + 2(3) = 6
-x + 6 = 6
-x = 6 - 6
x = 0

x = 0