What is the standard form of y= (-x + 2)(7x + 4 ) ?

Feb 14, 2016

$y = 7 {x}^{2} - 10 x + 8$

Explanation:

$y = \left(- x + 2\right) \left(7 x + 4\right)$

First we can multiply the two binomials using the FOIL method:

$\underline{F} i r s t = - x \cdot 7 x = - 7 {x}^{2}$

$\underline{O} u t e r = - x \cdot 4 = - 4 x$

$\underline{I}$$n$$n$$e r = 2 \cdot 7 x = 14 x$

$\underline{L} a s$$t = 2 \cdot 4 = 8$

Now combine them:

$\rightarrow - 7 {x}^{2} - 4 x + 14 x + 8$

$\rightarrow = - 7 {x}^{2} - 10 x + 8$

So in Standard form:

$\Rightarrow y = - 7 {x}^{2} - 10 x + 8$

Feb 14, 2016

Standard form of y=(−x+2)(7x+4) is $y = a {x}^{2} + b x + c$

Explanation:

Expanding y=(−x+2)(7x+4)

$y = - 7 {x}^{2} + 14 x - 4 x + 8$ or $y = - 7 {x}^{2} + 10 x + 8$

Hence standard form of y=(−x+2)(7x+4) is $y = a {x}^{2} + b x + c$