Appendix 1: Proofs in Mathematics | A1.2

Question 4

Given that y=x2+6y = x^2 + 6 and x=1x = -1, what can we conclude about the value of yy?

Check your answer with HomiSolve it yourself, then let Homi check your steps and spot mistakes.
Solution

We will put the given value of xx into the equation for yy.

Step 1 — Calculate y

We are given the equation for yy.

We are also given the value of xx.

Let's substitute x=1x = \mathbf{-1} into the equation.

y=x2+6y = x^2 + 6

y=(1)2+6y = (-1)^2 + 6

y=1+6y = 1 + 6

y=7\boxed{y = 7}

Answer

(i) y=7y = 7

More questions in A1.2

Q1

Given that all women are mortal, and suppose that A is a woman, what can we conclude about A?

Q2

Given that the product of two rational numbers is rational, and suppose aa and bb are rationals, what can you conclude about abab?

Q3

Given that the decimal expansion of irrational numbers is non-terminating, non-recurring, and 17\sqrt{17} is irrational, what can we conclude about the decimal expansion of 17\sqrt{17}?

Q4

Given that y=x2+6y = x^2 + 6 and x=1x = -1, what can we conclude about the value of yy?

Q5

Given that ABCD is a parallelogram and B=80\angle B = 80^\circ. What can you conclude about the other angles of the parallelogram?

Q6

Given that PQRS is a cyclic quadrilateral and also its diagonals bisect each other. What can you conclude about the quadrilateral?

Q7

Given that p\sqrt{p} is irrational for all primes pp and also suppose that 3721 is a prime. Can you conclude that 3721\sqrt{3721} is an irrational number? Is your conclusion correct? Why or why not?

← Back to Appendix 1: Proofs in Mathematics