Question

word problem...?
class 8th
maths​

Answer 1

Answer:

18)   Algebric expression to be subtracted

(3a²-6ab-3b²-1) - (4a²-7ab-4b²+1)

=3a²-6ab-3b²-1-4a²+7ab+4b²-1

=-a²+ab+b²-2

    or  

=a²-ab-b²+2

19) The perimeter  

of the rectangle will be the sum of the two adjacent sides multiplied by 2.

P=2(2x²-5xy+3z²+4xy-x²-z²)

=2(2x²-x²-5xy+4xy+3z²-z²)

=2(x²-xy+2z²)

=2x²-2xy+4z²

The perimeter of the rectangle is 2x²-2xy+4z².

20) Step 1 of 3

Use given information

Perimeter of triangle, p=6p²-4p+9 …………………(1)

Two sides of a triangle are a, b and c.

First side, a=p²-2p+1 …………………….(2)

Second side, b=3p²-5p+3 …………………….(3)

Let the third side be c

Step 2 of 3

Use formula of perimeter of triangle, P  

P=a+b+c

Put the value of P, a and b from equation (1), (2) and (3)

P=a+b+c

6p²-4p+9=p²-2p+1+3p²-5p+3+c

c=(6p²-4p+9)-(p²-2p+1+3p²-5p+3)

c=6p²-4p+9-p²-1-3p²+5p-3    ……………..(4)

Step 3 of 3

Separate each term of, p² and p in equation (4)

c=(6p²-p²-3p²)+(-4p+2p+5p)+(9-1-3)

c=p²(6-1-3)+p(-4+2+5)+(9-1-3)

c=p²(6-4)+p(-4+7)+(9-4)

c=p²(2)+p(3)+(5)

c=2p²+3p+5

Hence, the required side is c=2p²+3p+5

The required side is c=2p²+3p+5

Step-by-step explanation: