When I expand (2x + 7)(x - 1), I get 2x^2 + 5x - 7.
I can use my calculator to help me check if my answer is correct.
For instance, if x = 2,
(2x + 7)(x - 1) = 11
and
2x^2 + 5x - 7 = 11
That means I have done my expansion correctly.
I can safely say, I can do this with any value of x and for any given expression.
Do you agree? Justify your argument with example(s).
No. If x is 0 and if is something/x it would be undefined.
ReplyDeleteNo. if x=3
ReplyDelete2(x)^2+5x-7=2(3)^2+5(3)-7=26
No. x may be 0 (highly unlikely) and then it will be wrong
ReplyDeleteI do not agree. It works almost all the time, but if the x is 0, the equation will not work.
ReplyDeleteIt does not apply to all numbers.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteno if x is 0 or (-2) then it will wrong
ReplyDeleteDose not works with all the number
ReplyDeleteNo. If x = 0 or x = 1/3 or other fractions that cannot be converted into a decimal.
ReplyDeleteNo. There is a chance it might be zero, then the answer will be different.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteNo, I would not work all the time.
ReplyDeletee.g. Let x be 5.
(2x + 7)(x - 1)=68
2x^2 + 5x - 7=118
If the value of X increases, the value of the equation gets higher. Since ^2 is exponential, that means that 2^2=4, but if you use a bigger number like 3^2=9, it is different.
ReplyDeleteExample:
Assume that X is 4,
2X4^2 + 5X4 - 7 = 45, not 11.
No, I do not agree as x can also be a negative number and
ReplyDeleteFor instance, if x is -2
(2x+7)(x-1)=(-4+7)(-2-1)=3*-3=-9
and
2x^2 + 5x - 7 = 16-10 + -7 = -1
It does not apply all the time when x=3
ReplyDeleteI do not agree as all the other values cannot work.
ReplyDeleteNO. Example, if the question is x/x-5 - 3/x+7, and the value of x is 5, the denominator would be 0, and the calculator would have an error.
ReplyDelete(stated by ms loh xD)
Let x = 11
ReplyDelete2(x)^2+5(x)-7
= 2(11)^2+5(11)-7
= 22^2+55-7
= 484+55-7
= 534
:O
It works with all whole numbers except for 5 and 0.
ReplyDelete