What is the value of (2x^2-5x+4)if x =7

We have to use PEMDAS for this expression.

Parentheses
Exponents
Multiplication
Division
Addition
Subtraction

(2x^2 - 5x + 4)                    Original Mathematical Expression

[2(7)^2 - 5(7) + 4]                 Plugging the value of x, 7 into expression.

There are parentheses, so that means we have to work in them.

There are exponents, so we have to do those first.

[2(49) - 5(7) +4]                    Exponents.

There is multiplication, that we can do, so we do that left to right.

[98 - 35 + 4]                         Multiplication.

There is no division.

There is addition and subtraction, so we do those left to right.

[63 + 4]                                Subtraction.

67                                        Addition.

Final 67