Question

Which equation shows a correct evaluation of (mn)(4)?
m(x) = 4x-5
n(x) = 2x + 11
A.
(mn)(4) = 8(4) - 55
B.
(mn)(4) = 8(4)2 + 34(4) - 55
C.
(mn)(4) = 8(4)2 - 55
D.
(mn)(4) = 8(4)2 - 6(4) - 55

Answer 1

Answer:

$(mn)(x) =8(4^2) +34(4) - 55$

Step-by-step explanation:

Given

$m(x) = 4x - 5$

$n(x) = 2x + 11$

Required

What is (mn)(4)?

In functions:

$(mn)(x) = m(x) * n(x)$

Substitute values for m(x) and n(x)

$(mn)(x) = (4x - 5)(2x + 11)$

Substitute 4 for x

$(mn)(x) = (4*4 - 5)(2*4 + 11)$

$(mn)(x) = (4^2 - 5)(8 + 11)$

$(mn)(x) =8(4^2) - 8*5 + 11(4^2) - 11 * 5$

$(mn)(x) =8(4^2) - 40 + 176 - 11 * 5$

$(mn)(x) =8(4^2) +136 - 55$

$(mn)(x) =8(4^2) +34(4) - 55$