7 is decreased by 2 multiplied by 4

Answer 1

7 - (2 x 4) = 7-8 = -1

or

(7-2) x 4 = 5x4 = 20

People less mathematical would go with 20

as that seems to track the English language, go left to right

But mathematicians have this technical "order of operations" PEMDAS

P parentheses

E exponents

M multiplication

D division

A addition

S subtraction

M comes before S, you need to multiply 2 by 4 before subtracting the result from 7, to get -1

So. Hard to tell what the problem really was intended to be, A fanatical mathematician would go with -1.

a sane person into the English language more would go with 20