Question

6.03] If you wanted to eliminate the y variable by adding the two equations in the following system, what could be your first step?
3x + y = 6
4x − 5y = 10

Multiply the first equation by 5.

Multiply the first equation by −5.

Multiply the first equation by −4.

Add the two equations together.

Question 5 (Multiple Choice Worth 4 points)

[6.02] For the following system, if you isolated x in the second equation to use the Substitution Method, what expression would you substitute into the first equation?

3x + y = 8
−x − y = −7

−y + 7

−y − 7

y + 7

y − 7

Answer 1

6.03) You would multiply the first equation by 5.

This is because:

(1) 3x + y = 6 (Multiply by 5 = (2) )
+ 4x − 5y = 10

(2) 15x +5y = 30
+ 4x - 5y = 10 (add x's, y's and 30 + 40 = (3) )

(3) 19x +0y = 40 (times y by 0 = (4) )

(4) 19x =40

Answer 2

[6.02] -y +7

This is because:

(1) −x − y = −7 (leave x on its own and move -y to the other side to get (2) )

(2) -x = -7 + y (multply (-7+y) by negative (-) to get (3) )

(3) x = 7 - y (switch 7 and y around to get the answer that is required in choices (4) )

(4) x = -y + 7 (answer)

Answer 3

The answer would be A) Multiply the first equation by 5. because
(3x + y = 6)5
4x − 5y = 10

15x + 5y = 30
+ 4x - 5y = 10
19x = 40
(19x)/19 = (10)/19

x\[\approx0.53\]

Answer 4

thank you and whats the foil method?? and how would you apply it