To eliminate the [tex]\( x \)[/tex] terms and solve for [tex]\( y \)[/tex] in the fewest steps, by which constants should the equations be multiplied before adding the equations together?

First equation: [tex]\( 6x - 5y = 17 \)[/tex]
Second equation: [tex]\( 7x + 3y = 11 \)[/tex]

A. The first equation should be multiplied by 3 and the second equation by -5.
B. The first equation should be multiplied by 3 and the second equation by 5.
C. The first equation should be multiplied by 7 and the second equation by -6.
D. The first equation should be multiplied by 7 and the second equation by 6.



Answer :

Let's approach this step by step to understand which constants should be used to multiply each equation to eliminate the [tex]\( x \)[/tex] terms.

We start with the two given equations:
1) [tex]\( 6x - 5y = 17 \)[/tex]
2) [tex]\( 7x + 3y = 11 \)[/tex]

To eliminate the [tex]\( x \)[/tex] terms, we need to make the coefficients of [tex]\( x \)[/tex] in both equations equal (but opposite in sign). The coefficients of [tex]\( x \)[/tex] in the equations are 6 and 7, respectively.

To make these coefficients equal, we can multiply the first equation by the coefficient of [tex]\( x \)[/tex] in the second equation, and vice versa. Specifically, we will multiply:

- The first equation by 7
- The second equation by -6

Thus, the equations become:
1) [tex]\( 7 \times (6x - 5y) = 7 \times 17 \)[/tex]
which simplifies to:
[tex]\( 42x - 35y = 119 \)[/tex]

2) [tex]\( -6 \times (7x + 3y) = -6 \times 11 \)[/tex]
which simplifies to:
[tex]\( -42x - 18y = -66 \)[/tex]

Now we see that the coefficients of [tex]\( x \)[/tex] (42 and -42) are equal in magnitude but opposite in sign, allowing us to eliminate the [tex]\( x \)[/tex] terms by adding the two equations together.

So the constants to multiply the equations by are:
- Multiply the first equation by 7
- Multiply the second equation by -6

Thus, the correct answer is:
The first equation should be multiplied by 7 and the second equation by -6.