Question

Tick (✓) the correct answer:
If x = 10, then the value of (4x² + 20x + 25) = ?
(a) 256
(b) 425
(c) 625
(d) 575

Answer 1

(c) 625

$$\begin{gathered} \left(4x^2+20x+25\right) \\ \Rightarrow {\left(2x\right)}^2+2\left(2x\right)\left(5\right)+{\left(5\right)}^2 \\ \Rightarrow {\left(2x+5\right)}^2 \\ \Rightarrow {\left(2\left(10\right)+5\right)}^2 \\ \Rightarrow {\left(20+5\right)}^2 \\ \Rightarrow {\left(25\right)}^2 \\ \Rightarrow 625 \end{gathered}$$