MTH( F.2數學題)

(A - B)x + (A + B) ≡ 7x + 3

Since this is an identity. So, this equation is always true for all values of x

Comparing the coefficient,

A - B = 7 ─── (1)

A + B = 3 ─── (2)

(1) - (2):

(A - B) - (A + B) = 7 - 3

-2B = 4

B = 4/(-2)

B = -2

So, sub B = -2 into (1):

A - (-2) = 7

A + 2 = 7

A = 5

(A-B)x + (A+B) ≡ 7x + 3

A = 5 / b = -2

find the values of A and B for the following identity in x:
(A-B)x + (A+B) ≡ 7x + 3
(A-B)x + (A+B) ≡ 7x + 3
Ax-Bx+A+B=7X+3
Ax-Bx=7x
A-B=7
A=7+B--(1)
A+B=3--(2)
put (1) into (2)
7+B+B=3
2B=3-7
B=-2
put B=-2 into (1)
A=7+(-2)
A=5
so A=5,B=-2

(A-B)x + (A+B) ≡ 7x + 3
Ax-Bx+A+B=7X+3
Ax-Bx=7x
A-B=7
A=7+B--(1)
A+B=3--(2)
put (1) into (2)
7+B+B=3
2B=3-7
B=-2
put B=-2 into (1)
A=7+(-2)
A=5
so A=5,B=-2

(A-B)x + (A+B) ≡ 7x + 3
A-B=7 &
A+B=3

A = 5 and b = -2