Question

Please help me it would be a great honor for your help!!

Answer 1

y = 21, x = 6

Explanation:

Substitute y = 7x - 21

7x - 21 = x + 15

Isolate x for 7x - 21 = x +15

x = 6

For y = 7x - 21

Substitute x = 6

y = 7 * 6 - 21

Simplify

y = 21

Answer 2

(6,21)

Explanation:

There are two ways to solve a system of equations: mathematically by substitution, or by graphing.

Math Substitution:

y = x + 15

y = 7x - 21

Since both expression are equal to the same number, set them equal to each other:

x + 15 = 7x - 21

6x = 36

x = 6

Then use x = 6 in either equation to find y:

y = x + 15

y = 6 + 15

y = 21

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Graphically:

Graph both equations and find the solution for x and y where they intersect. See attachment. Intersection at (6,21)