Answer:
15.3
Step-by-step explanation:
18-(18×(15%))= 15.3
Eight *(a number) plus 5*(another number) is -13.
translates to:
8(x) + 5(y) = -13
The sum of (the number) and (the other number) is 1.
translates to:
(x) + (y) = 1
We have a system of two equations involving two unknowns: x and y.

We can easily solve the system using Substitution or Elimination. Let's use Elimination this time.
We'll multiply the second equation by -8 so that the x's match up.

When we add the equations together, the x's will fall out of the equation, summing to zero. The 5y and -8y will sum to -3y and the right hand side will sum to -21.

Divide by -3,

Plug back into one of your original equations to find the value of x,

Subtract 7,
1. A
Since parallel lines never cross, then there can be no intersection; that is, for a system of equations that graphs as parallel lines, there can be no solution. This is called an "inconsistent" system of equations, and it has no solution.
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2. C
That's right. If a system of equations has a solution, then their graphs intersect, and the point where they intersect is the solution because it's the point that satisfies each equation in the system.
Straight-line graphs with the same slope are parallel lines, and they never intersect, which is another way of saying they have no solution.