Dado o seguinte sistema linear, qual o valor da diferença entre x e y?

!$ \left\{\begin{matrix} 3x & +2y & =118 \\ 4x & -y & =84 \\ \end{matrix}\right. !$

Qual o valor de x na seguinte matriz, sabendo que seu determinante é -28?

!$ \begin{matrix} 3 & 5 & 3 \\ 6 & 8 & 7 \\ x & 3 & 5 \\ \end{matrix} !$

Em uma progressão geométrica, o quarto termo é 171,5 e o terceiro termo é 49. Qual o primeiro termo?

Dois triângulos semelhantes têm bases de 40 cm e 50 cm respectivamente. Se o triângulo maior tem altura de 60 cm, qual a área do triângulo menor?

Choose the wrong use of the modal verb in the sentences below.

In real conditional sentences, we can often use either unless of if… not with a similar meaning. Choose a sentence with a wrong use of conditional clause.

Mark the right question according to English grammar.

Complete the sentence with the right verb form according to the modal: “She always felt bad for them, so she would (…) them scallion pancakes for breakfast.”

Some verbs can usually be followed by prepositions before the object of the verb. Complete the sentence with a right preposition: “I began to suffer (…) a blurring of vision I suspected was psychosomatic.”

We can put adverbs and adverb phrases at the front, in the middle or at the end of a clause. Choose the right position of the adverb below.