Home > Algebra > Systems Using Substitution

How do you solve the following system?: #8x +y =12, 7x -5y = -4#

Answer 1

Eli Assouline

#x=56/47#

In order to determine what y is equal to, I first rewrote one equation in this instance.

#8x+y=12#

Thus, we obtain:

#y=12-8x#

After that, we apply it to the other equation to obtain:

#7x-5(12-8x)=-4#

Which is:

#7x-60+40x=-4#

Condensed:

#7x+40x=56#

#47x=56#

#x=56/47#

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 2

Julia Adams

To solve the system of equations (8x + y = 12) and (7x - 5y = -4), follow these steps:

Multiply the first equation by 5 and the second equation by 1 to eliminate the variable (y).
This gives us (40x + 5y = 60) and (7x - 5y = -4).
Add the equations together to eliminate (y): (40x + 7x = 60 - 4).
Simplify: (47x = 56).
Solve for (x): (x = \frac{56}{47}).
Substitute (x) back into one of the original equations to solve for (y).

So, the solution to the system is (x = \frac{56}{47}) and (y = \frac{84}{47}).

By signing up, you agree to our Terms of Service and Privacy Policy

Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.