sհօա ԵհαԵ (3x+7)2-84x=(3x-7)2
{2=(ɾαísҽժ Եօ Եհҽ թօաҽɾ)}
Answers
Answer:
LHS = (3x + 7) - 84x
= (3x)2 +2(3x)(7) + (7)2 - 84x
= 9x2 + 42x + 49 - 84x
= 9x2 + (42 - 84) x + 49
= 9x2 -42x + 49
RHS = (3x - 7)2
= (3x)2 -2(3x)(7) + (7)2
= 9x2 - 42x + 49
Since, LHS = RHS
∴ (3x + 7)2 -84x = (3x -7)2
(3x+7)²-84x=(3x-7)²
Hence proved
Step-by-step explanation:
GIVEN EQUATION: (3x+7)²-84x=(3x-7)²
Show that LHS = RHS
LHS = (3X+7)²-84x
RHS = (3X-7)²
STEP 1 :
Expand the LHS
Expand (3x+7)² = (3x)²+2(3x)(7)+49
==>9x²+(6x)(7)+49
==>9x²+42x+49
STEP 2:
Applying the formula
We know that,
(a+b)²=a²+2ab+b²
Applying this equation on LHS
LHS = (3x+7)²-84x
LHS = 9x²+42x+49-84x
LHS = 9x²+42x-84x+49
LHS = 9x²-42x+49
we know that,
(a-b)²=a²-2ab+b²
LHS = (3x)²-42x+7²
LHS = (3x-7)²
RHS = (3x-7)²
LHS = RHS