Hi there. You're right; the previous sentence is the second conditional with a dependent clause that needs to be in the subjunctive mood. It should read, If English test "were" difficult,... But, you also need to add the article "the' before the word "English." And, again, you need to add "the" before "math." Additionally, the word "difficulty" here is incorrect. You need the adjective form, "difficult," instead of the noun form "difficulty." Adjectives, as I'm sure you remember, modify nouns and pronouns. "Difficult," in this case, modifies the verb "test." I hope this helps.

Here are some examples. I hope they are helpful. In some situations, you need to use "also" rather than "so". "She is beautiful. So is her sister." "She is beautiful. Her sister is also." "The English test was difficult. So was the math test." "The students would fail the English test. So would they fail the math test." "The students would fail the English test. They would also fail the math test." "The students would fail the English test, and also the math test." With your conditional sentence, you could do any of these: "If the English test were difficult, students would fail it. The same is true of (or "for") the math test." "If the English test were difficult, students would fail it. So would they fail the math test if it were difficult. "If the English test were difficult, students would fail it, and likewise for the math test."