For what do "x" and "a" stand? I think you have defined "x" to be "my original weight" and "a" to be "the weight of the food I ate" or "the weight added by four plates of fruit". If so, your equations look fine.

You have created a "system" of equations. There are many methods for solving a system of linear equations, but I would suggest simplifying and then using "addition".

First, study a fewonline lessonsto learn the basics. Then:

. . . . .1.10x = 1x + 1a + 10

. . . . .1.11x = 1x + 2a + 10

. . . . .0.10x = 1a + 10

. . . . .0.11x = 2a +10

. . . . .10x = 100a + 1000

. . . . .11x = 200a + 1000

Multiplying the first equation by -2, you get:

. . . . .-20x = -200a - 2000

. . . . ..11x = .200a + 1000

Add down, and solve for the value of x. Then back-substitute to solve for the value of a.

Have fun!