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CTET Paper II (Mathematics and Science) 7 Jan 2022 Solved Paper

Question : 38 of 150

Marks: +1, -0

If 7x - 1 = 48, then the value of 2x^{3} + 3x is

Solution:

Concept:

Solve the linear equation to find

x

. Then substitute into the expression to get the value.

Explanation:

Given

7x - 1 = 48

. Add 1 to both sides:

7x = 49

. Divide by 7:

x = 7

Now find

2x^{3} + 3x

. Substitute

x = 7

2(7)^{3} + 3(7) = 2(343) + 21 = 686 + 21 = 707

Answer:

707, which is option A.

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