Answer:
[tex]C. \[/tex] [tex]\frac{1}{2}x^3 + 3.4y = 21[/tex]
Step-by-step explanation:
Given
[tex]x = 2[/tex]
[tex]y = 5[/tex]
Required
[tex]\frac{1}{2}x^3 + 3.4y[/tex]
Substitute 2 for x and 5 for y;
The expression becomes
[tex]=\ \frac{1}{2} * 2^3 + 3.4 * 5[/tex]
Multiply 3.4 by 5
[tex]=\ \frac{1}{2} * 2^3 + 17[/tex]
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[tex]2^3 = 2 * 2 * 2 = 8[/tex]
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[tex]=\ \frac{1}{2} * 8 + 17[/tex]
[tex]=\ \frac{8}{2} + 17[/tex]
[tex]=\ 4 + 17[/tex]
[tex]=\ 21[/tex]
Hence;
[tex]\frac{1}{2}x^3 + 3.4y = 21[/tex]