Paste this into a new Tampermonkey script and press ALT + I to get the answers.

blinklearning_hack.js

// ==UserScript==
// @name         BlinkLearning Solver by Auax
// @namespace    http://tampermonkey.net/
// @version      0.2
// @description  Simple cheat for BlinkLearning!
// @author       Auax
// @match        www.blinklearning.com:/*
// @icon         https://www.google.com/s2/favicons?domain=blinklearning.com
// @grant        none
// ==/UserScript==

// Thanks Google Dev console!

(function () {
    'use strict';
    console.log("RUNNING userscript by Auax");

    // let classes_ = ".js-correct, .js-save, #t1-corrector, #t2-corrector, .review, .repetible";
    let classes_ = ".js-correct, .js-save";

    // Get solutions or hide them when pressing alt + i
    document.addEventListener('keydown', function (event) {
        if (event.altKey && event.key === 'i') {
            let askContinue = window.confirm("Would you like to continue? The check button will be enabled.");
            if (askContinue) {

                // Get elements using the specified classes
                let elements = $(classes_);

                // Only execute if there's elements
                if (elements.length > 0) {

                    // Iterate over all of the elements
                    elements.each(function (i, el) {
                        // Check the element is a button
                        if (el.tagName.toLowerCase() == "button") {
                            el.disabled = false; // Enable element
                            el.style.backgroundColor = "red"; // Red bg

                            // Replace click binding method with custom func
                            $(el).unbind("click").click(function (e) {
                                // Magic
                                var $this = $(this),
                                    $slide = $this.closest('.js-slide-wrapper'),
                                    prefix = 't' + $slide.data('slide-index'),
                                    slide = window[prefix + '_slide'];

                                // Show solution
                                slide.showSolution();
                                let wantToCorrect = window.confirm("Would you like to send the exercice? (Will send current values, not the correct ones)");
                                if (wantToCorrect) {
                                    slide.hideSolution();
                                    correct(prefix, true, true);
                                }

                                alert("Reopen the exercice to unblock it.");

                                e.preventDefault();
                                e.stopImmediatePropagation();
                            });
                        }

                    })
                }

                else {
                    alert("Couldn't find element in 'elements' with length 0!");
                }
            }
        }
    });
})();

Thoroughly broken. Not sure why, and I'm not a programmer, so I can't solve it, but it's worth noting.

Sorry, I haven’t updated it for like 2 years since I no longer have access to blink learning. So I cannot offer a solution if it doesn’t work anymore. They probably changed the website thus breaking the code I wrote.