Question
How much does $a^2-3 a b+2 b^2$ exceed $2 a^2-7 a b+9 b^2 ?$
✓
Answer
Required expression:
$=\left(a^2-3 a b+2 b^2\right)-\left(2 a^2-7 a b+9 b^2\right)$
$=a^2-3 a b+2 b^2-2 a^2+7 a b-9 b^2$
Collecting positive and negative like terms together, we get
$=a^2-2 a^2-3 a b+7 a b+2 b^2-9 b^2$
$=-a^2+4 a b-7 b^2$
$=\left(a^2-3 a b+2 b^2\right)-\left(2 a^2-7 a b+9 b^2\right)$
$=a^2-3 a b+2 b^2-2 a^2+7 a b-9 b^2$
Collecting positive and negative like terms together, we get
$=a^2-2 a^2-3 a b+7 a b+2 b^2-9 b^2$
$=-a^2+4 a b-7 b^2$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
The performance of a student in $1st$ Term and $2nd$ Term is given. Draw a double bar graph choosing appropriate scale and answer the question:
In which subject, has the child improved his performance the most?
→| Subject | $1^{st}$ term(M.M.$100)$ | $2^{nd}$ term(M.M. $100)$ |
| English | $67$ | $70$ |
| Hindi | $72$ | $65$ |
| Maths | $88$ | $95$ |
| Science | $81$ | $85$ |
| S. Science | $73$ | $75$ |
Find the value of n, where n is an integer and $2^{\text{n-5}}\times6^{\text{2n-4}}=\frac{1}{12^{4}\times2}$
→$\text{x}-\frac{1}{3}=\frac{2}{3}$
→Compute the value of $x$ in each of the following figures:
→Four equal circles, each of radius $5\ cm$, touch each other as shown in Fig. Find the area included between them. (Take $\pi = 3.14).$
→Arrange the following rational numbers in descending order: $\frac{17}{-30},\frac{11}{-15},\frac{-7}{10},\frac{10}{5}$
→Suman studies for $5 \frac{2}{3}$ hours daily. She devotes $2 \frac{4}{5}$ hours of her time for Science and Mathematics. How much time does she devote for other subjects?
→In the given figure, $\text{l || m}$ and $\text{p || q}$ Find the measure of each of the angles $\angle\text{a},\angle\text{b},\angle\text{c}\ \text{and}\ \angle\text{d}.$
→Construct 4 pairs of parallel lines in different orientations.
Find the reciprocal of the rational number $\Big(\frac{1}{2}\Big)^{2}\div\Big(\frac{2}{3}\Big)^{3}$
→