Express x squared + 4 x -7 in the form (x+a) squared-b where a and b are integers

x² + 4x - 7 = (x + 2)² - 11

Step-by-step explanation:

Let us solve the question

∵ The expression is x² + 4x - 7

∵ The form is (x + a)² - b

→ To express the equation in the given form quate them

∴ x² + 4x - 7 = (x + a)² - b

→ Simplify the right side then equate the like terms to find a and b

∵ (x + a)²  = (x + a)(x + a)

∴ (x + a)² = (x)(x) + (x)(a) + (a)(x) + (a)(a)

∴ (x + a)² = x² + ax + ax + a²

→ Add the like terms

∵ (x + a)² = x² + (ax + ax) + a²

∴ (x + a)² = x² + 2ax + a²

→ Substitute (x + a)² in the right side by x² + 2ax + a²

∵ x² + 4x - 7 = x² + 2ax + a² - b

→ Equate the coefficients of the like terms

∵ 4x and 2ax are like terms

∴ 4 = 2a

→ Divide both sides by 2

∴ 2 = a

∵ -7 and a² - b are like terms ⇒ constant terms

∴ -7 = a² - b

∵ a = 2

∴ -7 = (2)² - b

∴ -7 = 4 - b

→ Subtract 4 from both sides

∵ -7 - 4 = 4 - 4 - b

∴ -11 = -b

→ Divide both sides by -1

∴ 11 = b

→ Substitute the values of a and b in the given form

∴ (x + a)² - b = (x + 2)² - 11

∴ x² + 4x - 7 = (x + 2)² - 11

the answer is 13 cm

4+4+2x

or

2x+8

step-by-step explanation: