In order to solve the following system of equations by subtraction, which of
the following could you do before subtracting the equations so that one
variable will be eliminated when you subtract them?
4x – 2y=7
3x – 3y=15

A. Multiply the top equation by-3 and the bottom equation by 2.

B. Multiply the top equation by 1/3.
C. Multiply the top equation by 3 and the bottom equation by 4.

D. Multiply the top equation by 15 and the bottom equation by 7.

I think it's C.Multiply the top equation by 3 and the bottom equation by 4

Step-by-step explanation:

Multiplying the top equation by 3 you get:

3(4x – 2y) = 3∗7

12x - 6y = 21          (eq.1)

Multiplying the bottom equation by 4 you get:

4(3x – 3y) = 4∗15

12x - 12y = 60       (eq.2)

Now, if you subtact eq.2 from eq.1 you get:

(12x - 6y = 21 )

-

(12x - 12y = 60)

0x + [- 6y -(-12y)] = 21 - 60

Carrying out the calculation you get:

6y = -39

y = -39/6

y = -13/2

the equation for this situation is y=122+45. to solve the equation you would add 45 and 122 to get a total of 167lbs. in conclusion, grace's weight eight weeks ago was 167lbs.