It can be so frustrating to know that you did everything that you could do and yet it wasn’t good enough. Just know that you are far ahead of those who took algebra all those years ago and remember nothing!
But more importantly, remember that you have the the mind of Christ:

1 Corinthians 2:16 “For who has understood the mind of the Lord so as to instruct him?” But we have the mind of Christ.

And wisdom that comes from God:

1 Corinthians 1:30 He is the source of your life in Christ Jesus, whom God made our wisdom and our righteousness and sanctification and redemption.

And that is so much more valuable than algebra (though math is very important as I keep telling my Sarah).
I’m praying for you as well. I know that you will persevere because you know how important it is to demonstrate to your daughters the importance of facing your failure and not allowing it to defeat you or stand in the way of your goals.