Answer :

[tex]f(g(x))=3(2x+a)^2-7\\\\ 3(2\cdot0+a)^2-7=68\\ 3(2+a)^2=75\\ (a+2)^2=25\\ a+2=5 \vee a+2=-5\\ a=3 \vee a=-7[/tex]

The value of a is equal to +5 and -5.

What is an expression?

Expression in maths is defined as the collection of the numbers variables and functions by using signs like addition, subtraction, multiplication, and division.

The value of a is calculated as:-

3x² - 7 = 68

3 ( 2x + a)² -7 = 68

Put x = 0

3 ( a ) ² = 75

a ² = 75 / 3

a  = √25

a = ±5

Therefore, the value of a is equal to +5 and -5.

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