Tina picked three chits from a bowl that had chits with expressions written on them. She got $(3 x^{2} + 5 x - 7)$ , $(- 7 x + 9)$ , and $(- 2 x^{2} + 3 x + 4)$ in her chits. Her friend asked her to find the sum of the first two expressions and subtract the third expression from the sum. What would be the final expression after solving?

x^{2} - x + 6

No worries! We‘ve got your back. Try BYJU‘S free classes today!

5 x^{2} - 5 x - 2

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

x^{2} + x + 6

No worries! We‘ve got your back. Try BYJU‘S free classes today!

5 x^{2} + 5 x + 2

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is B $5 x^{2} - 5 x - 2$
Let's make a table with Tina's expressions.

Pages read

1st expression $(3 x^{2} + 5 x - 7)$

2nd expression $(- 7 x + 9)$

3rd expression $(- 2 x^{2} + 3 x + 4)$

According to her friend's instructions, she needs to add the first two expressions and subtract the third from that. We get:
$= (3 x^{2} + 5 x - 7) + (- 7 x + 9) - (- 2 x^{2} + 3 x + 4)$
$= (3 x^{2} + 5 x - 7) + (- 7 x + 9) + (2 x^{2} - 3 x - 4)$

By combining the like terms, we get:
$(3 x^{2} + 2 x^{2}) - ----------- - + (5 x - 7 x - ------- - - 3 x) + (- 7 + 9 - ------ - - 4)$

By simplifying the underlined terms, we get:
$= 5 x^{2} + (- 2 x - 3 x) + (2 - 4)$

$= 5 x^{2} - 5 x - 2$

Therefore, Tina's final expression after solving according to her friend's instructions is $5 x^{2} - 5 x - 2 - ------------ -$ .

Suggest Corrections

Similar questions

Q. Jenny and her friends picked out some paper chits from a glass bowl. Each of these chits had some numbers on them.
Jenny's chit had the number 16.
Kaira's chit had a number that was the square root of the number on Jenny's chit.
Also, Sia's chit had a number that was the square root of the number on Kaira's chit.

Which of the following numbers appeared on Sia's chit?

Q. A box has ten chits numbered

0, 1, 2, 3, . . . . ., 9

. First, one chit is drawn at random and kept aside. From the remaining, a second chit is drawn at random. What is the probability that the second chit is drawn at random. What is probability that the second chit drawn is "

9

Seven chits are numbered $1$ to $7$ . Four chits are drawn one by one with replacement. The probability that the least number appearing on any selected chit is $5$ , is

Q. Seven chits are numbered from 1 to 7. Four are drawn one by one with replacement. The probability that the least number on any selected chit is 5 is

Q. To pick a lab partner, each student must write his/her name down on a piece of paper and drop it into a bowl. Students would then pick the pieces of paper from that bowl to get their lab partners. Given that Kevin was the first one to pick a chit and he has 5 friends in his class and there are 20 students in the class, what is the probability that Kevin's partner will be one of his friends?

Join BYJU'S Learning Program

	Pages read
1st expression	$(3 x^{2} + 5 x - 7)$
2nd expression	$(- 7 x + 9)$
3rd expression	$(- 2 x^{2} + 3 x + 4)$