Question

If x = −2, find the value 5x2− 3x − 4.​

Answer 1

Answer:

5x - 2 = 3x - 4

is a linear algebraic equation in one variable x . We have to find x. Th procedure consists of gathering all x-terms on one-side and the constant terms on the other and then solve for x.

Step 1:

Take 3x to left side of the equation and -2 to the right side remembering that in every such transposition there is a change of sign.

∴ 5x - 3x = 2 - 4

Step 2:

Simplify both sides.

∴2x = -2

Step 3:

Divide both sides by 2.

∴2x/2 = -2/2

Step 4:

Simplify both sides .

Therefore, 1.x = -1

⇒ x = -1 (Answer)

Check: Substituting for x = -1,

L.H.S.= 5x - 2 = 5 (-1) - 2 = -5 - 2 = -7

R.H.S.= 3x - 4 = 3(-1) - 4 = -3 - 4 = -7

∴ L.H.S. = R.H.S.

Hence x = -1 is the right solution.

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Answer 2

Step-by-step explanation:

Ans: 5x^2 - 3x - 4.

5(-2)^2 - 3(-2) - 4.

5(4) + 6 - 4.

20 + 2.

22.