Question

The sum of two Numbers is 9 the difference between five times of first and four times of second is 9 what are the numbers

Answer 1

x+ y = 9 AND 5x - 4y = 9.

Solving the first eqaution for y, y = 9 - x.

Then substituting the first equation into the second:

5x - 4(9 - x) = 9 --> 5x - 36 + 4x = 9 --> 9x - 36 = 9.

Adding 36 to both sides --> 9x -36 + 36 = 9 + 36 --> 9x = 45.

Divide both sides by 9 --> 9x/9 = 45/9 --> x = 5.

Not finished yet since we still must go back to find y by subsititing the known value of x into either of the orginal equations --> 5 + y = 9

Substact 5 from both sides --> 5 + y - 5 = 9 - 5 --> y = 4

Therefore x = 5, y = 4